300 episodes? Seriously? Seriously.

In age dominated by TV series favoring seasons of 13 episodes or less, finite conclusions and ambiguous off-broadcast ratings, it’s a rare network show indeed that hits the once-vaunted 300-episode milestone. On Thursday Nov. 9, “Grey’s Anatomy” does just that, and even after 14 seasons and a dramatically changing television landscape, the durable medical drama has proven to be a survivor with a still-healthy prognosis without ever having been on life support.

The landmark episode, titled “Who Lives, Who Dies, Who Tells Your Story,” consciously celebrates the occasion with a tacit nod to the tumultuous history of the many generations of relationship-challenged healers at Grey-Sloan Memorial Hospital and the storytelling style spearheaded by creator Shonda Rhimes.

“I wanted to look back and move forward simultaneously – that was the challenge that I gave myself and the writers’ room,” the show’s executive producer and current showrunner Krista Vernoff, who’s been with the series since its debut season in 2005, tells Variety. “We came up with creative ways to remember the roots of the show, to remember the original cast, to remember some stories we have told, or maybe not finished telling. And also, to move the lives of the present day cast forward.”

Vernoff shares that when they were shooting in Seattle in the early part of the season, she already had the 300th episode in mind because it is such an important milestone. The inspiration behind the current hospital staff encountering patients who are dead-ringer doppelgangers for now-departed “Grey’s” characters came from her walking around set and seeing their stand-ins, one of whom “looked so much like Season One Katherine Heigl that I felt like I was traveling back in time.”

“We actually went looking for that stand-in, tried to find out if she was an actor, and in fact she was,” reveals Vernoff. “We brought her here to play that role. One day if she’s famous, that’s a pretty great breaking-in story!”

James Pickens Jr., who has played Dr. Richard Webber throughout the series’ entire run, thinks the show did a great job of finding those actors to take the show (and its audience) down a memory lane of sorts in its big episode. “I really had to do a double take!” he says. “They had the mannerisms down, the speech patters, it was really something. I got a little melancholy thinking about those great actors.”

When it came to breaking the story that would see the core characters encountering these doppelgangers, Vernoff says it came from a place of “what story do I want to tell, what feels earned, and what feels true, and what feels owed?” She hopes some of the dangling emotional threads with the show’s expansive ensemble provides a little added closure for longtime viewers. And yes, of course she admits she sprinkled in some Easter eggs, too.

As the second longest-running medical drama in network history, “Grey’s” is well within shooting distance of the recorder holder “ER” (331 episodes), and as the creative team gathered at Tao in Hollywood to celebrate the show’s accomplishment, there was an optimistic prognosis that “Grey’s” might even have the longevity to join the rarefied 600-plus ranks of “The Simpsons” and “Gunsmoke.” “Ellen and I have a pact: as long as the two of us want to do it and as long as we both feel creative while doing it [we’ll do it],” says Rhimes. “My vision for it is that as long as there’s good story to tell, I’m in.”

In the meantime, cast and crew offered a fond look at the show’s seismic impact then and now, on television, the culture, Hollywood and themselves.

Rhimes (creator; executive producer): “My daughter was just three months old when I wrote the script, and I remember thinking, ‘I have no idea what I’m doing with this baby.’ There’s something about that idea of you don’t know what you’re doing in your job, and on a bad day you could kill someone. I remember being obsessed with that idea: that on a bad day, if you make a mistake on a job where someone could die, it’s the most terrifying thing ever. I was also really wanting to watch a show where women behave like women I knew, like they weren’t all nice and nobody was someone’s wife or girlfriend, they were the main character. That was really what it was about. And also, I love surgery – I would watch those crazy surgery documentaries!”

Chandra Wilson (director; actress, Dr. Miranda Bailey): “Our journey basically was that we got the opportunity to show four of our episodes while ‘Boston Legal’ was on hiatus for four weeks – that’s all [ABC] gave us! We got to come in after ‘Desperate Housewives’ for four episodes, so we didn’t even have a time slot. Those four episodes apparently did kind of well, and they decided, ‘Well no, let’s not bring ‘Boston Legal’ back for the rest of the season – let’s show four more ‘Grey’s.’ That will be eight episodes and that will be their first season. Then we’re going to start right away and show them all over again.’ That’s kind of how we jumped out of the cannon. It was just this weird, unorthodox kind of way, with no time slot.”

Betsy Beers (executive producer): “I don’t think we ever set out to change the culture. I think we definitely set out to start a show that we really wanted to watch. I think certainly when we were talking about the development of the show, part of it was there wasn’t anything on television quite what we were looking for, that really depicted who we were, which were strong, complicated women who really, really loved our jobs and weren’t terrified to compete with our friends, and had messy, screwy relationships, I think it came from a place of, this feels real and true to us.”

Vernoff: “What’s incredible is that medicine is evolving faster than the show could possibly keep up. So we have, at any given time, three or four doctors in the writers’ room, and we can’t tell all the stories they give us. They tell us things they’ve witnessed, things they’ve experienced, research that is happening that’s cutting edge that they may have participated in. And we fill up boards, and by the end of the season, we barely made a dent. And because human beings continually evolve, we don’t really struggle for human stories either, because we have so many characters and there are so many evolutions.”

Beers: “There’s something about these characters and the way that Shonda created them, and the way that they’ve been written, where it’s almost like there is always something else to tell. Relatively early on it seemed clear that people came and went and you missed them, but you love the people who are there and that’s so much of what is really enticing for me and the fans. You continually get enamored of somebody new. I think it’s Shonda’s unique ability to create characters who are always totally three-dimensional and both strong and vulnerable at the same time, which keeps viewers coming back.”

Kim Raver (actress, Dr. Teddy Altman): “I love the way Shonda has been able to incorporate the human condition. She understands that there are moments where everyone’s struggling, and then there’s moments where we strive to have a great moment of being a hero. And I think she really understands that part of it. Also the underdog: how she really allows each character to have a moment where they’ve messed up, and to have a moment where they can redeem themselves.”

Vernoff: “Ellen Pompeo’s been there for 14 seasons, and fans have gotten to watch her grow up and change and evolve and survive – and not just survive the unthinkable, but thrive. Grieve and move forward and move on in a powerful, empowered and empowering way. I am so proud to write that character. I am so proud to work with that actress. It is extraordinary, I think, what she has provided in terms of role modeling for generations of young women, and it gives me chills to talk about it.”

Kelly McCreary (actress, Dr. Maggie Pierce): “The show is just really structurally sound. It’s a setting, fundamental characters, and a story structure that draws people in. What we do is bring in fresh blood, like we’ve got these new interns this season. We’ve got people going through all the changes of life, of marriage and divorce, kids, and death, and all of the things. For as changeable as life is, our show remains just as changeable.”

On the groundbreaking and influential strides the series made in representation, on screen and off:

Rhimes: “It’s odd to me that we have to consider ourselves female-forward and diversity-forward because it’s just normal life and it’s just the way the things are. It’s actually the other programming that’s behind the times. I don’t think we’re forward, I think we were normal, and everybody else was behind. It’s nice to see that other people are catching up.”

Debbie Allen (director; actress, Dr. Catherine Avery): ‘”I will never forget Shonda saying, ‘I don’t know why I’m getting an award for something that I do every day that everybody else should do.’ I thought that was brilliant. I think she, in many ways, shames people into “Hey, we need to be more like that.'”

Kim Raver: “You walk on that set, and there’s a woman director, there’s a woman editor, there’s a woman showrunner. There is something that she has done without pointing a finger at it, and sort of saying without saying it: ‘This is the way it should be.’ So she sets an example without making it an example, if that makes sense.”

Wilson: “I never saw myself as a series television director at all. I was approached, basically, by my producers in Season 4: ‘You know what, you should consider directing.’ Because I didn’t know any better, I said OK. I didn’t think it was appropriate to say no. I didn’t know anything. I spent the whole other season finally figuring out where the cameras were. I had no idea where the cameras were, ever. I would just come and do my show. By the time Season 6 rolled around and Bailey wasn’t so heavy in the episodes, I got my first shot. It’s been two episodes a season ever since.”

Kevin McKidd (director; actor, Dr. Owen Hunt): “I’ve directed 18 episodes now, and truly it’s the biggest kind of blessing I’ve ever had. Who gets that shot? Shonda and everybody here has supported that. Me and Chandra were the first two to direct to direct on the show, and now other people are doing it, too. What’s great about being a part of this company is that it feels like everybody is lifting each other up. Some of the P.As of the editing department are now the heads of the editing department in ‘Grey’s.’ People move up in the best kind of way.”

On crafting those wrenching water-cooler moments and facing fans’ – and actors’ –passionate reactions:

Allen: “You have actors that you trust, that they trust you, and you’re able to help them get through it. You have to know that the actors become these characters, and it’s real for them when they have to break apart, and it hurts them, so you have to midwife them in to it. You have to make them understand that this break up is going to be good: it’s what happens in life. It’ll add more energy to out storytelling. When Derek died, that was tough, it was really heartbreaking for everyone. People were mad, and I was like, ‘He’s not really dead – he’s actually racing cars in Paris right now. Calm down honey, calm down.'”

Jessica Capshaw (actress, Dr. Arizona Robbins): “[At the height of the Callie/Arizona romance] we didn’t know what was going on, we were just creating a story. We were just having fun, and then it sort of gathered steam and started meaning things to people. Once we saw how much it meant to people, and then it felt like something that we really needed to make sure that we took really good care of. That’s been, hopefully, what we’ve done. There’s a lot of pluses and minuses to social media, but the major-plus category is being able to hear from people how the shows are affecting them and what they feel, what they see, and how they think.”

Jason George (actor, Dr. Ben Warren): “Pre-social media [reaction from fans upset with your character] wasn’t that bad because you could just not open fan letters. But now you turn on your phone and you’ve got a truckload of messages saying, ‘Ben. you know you cut that woman open!’ ‘Ben, you leave Bailey alone.’ It’s nuts, but it’s also kind of fantastic because to be able to have that interaction with the fans is pretty spectacular. I’ve personally had folks reach out to me because we do stories that touch their family. I have a good, dear friend who is a 14-year-old, six-seven surgeries, multiple-cancer survivor, and kicking cancer’s ass. That came about because of Shonda Rhimes’ shows and social media. That kind of interface with the fans is pretty special.”

Camilla Luddington (actress, Dr. Jo Wilson): “I was one of those massive fangirls that was genuinely obsessed with McDreamy and Meredith being together. When Kate Walsh showed up at the end of Season 1, I was on the floor, super-dramatic about it! It took a long time to get accustomed [to being on the show] because I would geek out just all the time. I was like, ‘I’m in a scene with Bailey, oh my god and she’s yelling at me!’ I took a long time, but now it just feels like family. It’s very surreal being on a show that you’ve been a big fan of before.”

Caterina Scorsone (actress, Dr. Amelia Shepherd): “I was into it enough that when I finished watching the first season I thought I wanted to go to med school. [Joining the show] was incredible, it felt like walking into a dream, where you’re kind of like, ‘I dreamt that I was in the hospital in ‘Grey’s Anatomy,’” but there’s no roof, because that’s where the lighting goes.”

On the tradition of rotating romantic partners, where your lunch buddy at craft services is suddenly your make-out partner:

Luddington: “You almost can’t get attached to your own show couple, although it’s hard because you root for them. The next week you could open a script and you guys are fighting and it’s over. It’s difficult.”

Scorsone: “It never feels exploitative, it never feels like it’s just for titillation. It feels like it’s driving the story of people who are complicated and lonely. But yeah, sometimes it feels like you’re kissing your brother – but not for long!”

Capshaw: “Of course it’s awkward. You’re all of a sudden lying in bed and mock nakedness, making out. It’s funny, it’s interesting, it’s a very different kind of job.”

On internalizing a little too much of the medical jargon:

McKidd: “I definitely self-diagnosed myself with a couple things. I went ‘Wow, I actually knew what that was.’ But I wouldn’t trust my medical opinion on anything. If you have anything that’s going on, I wouldn’t trust me.”

Luddington: “I was pregnant all last season and I knew everything that could possibly go wrong in a pregnancy because of ‘Grey’s,’ which was horrifying, so I would diagnose myself all the time. I was like, ‘No, the doctors are wrong! I’m on ‘Grey’s Anatomy!'”

Pickens: “As actors, we’re always concerned about the longevity of our jobs. That’s just the nature of the business. But there was something about this show that it had such a head of steam. It was buoyed so much by its fanbase, that I never really had a concern about the longevity of the show. I think more than anything else, I was like, ‘How long can it go?’ And we still don’t know.”

Wilson: “I’m a soap opera person, so I still watch my ‘General Hospital’ and ‘Young and the Restless,’ and I feel like my fans are like me: when they have original characters that have been there from the beginning, they appreciate that, they come back for that, and they enjoy the journeys of these characters and getting to know us. The medical stuff continues to be fascinating. There’s something about longevity, where it’s kind of like coming home, when they come and play with us. That’s what we like to provide.”

Pickens: “The camaraderie! All of the babies that were born in these 14 years. I think I heard a comment somewhere that 33-34 babies had been born since the the show’s inception. That’s family. It’s become a family. It’s bigger than a TV show, and that longevity, you wouldn’t get anything like that. You probably won’t ever see it again, three hundred episodes, with the new platforms and streaming now. Just economically, you won’t see it.”

Beers: “If there was a secret, it’s that Shonda as a creator has never rested. She is always curious to try a different situation or push the characters harder. Poor Meredith Grey has been through a hell of a lot as a result, but I think that’s what we all kind of realize, is that’s how we all grow and change. I think that’s sort of the reason we keep on going.”

Rhimes: “I really thought, ‘Maybe we’ll do a pilot,’ and then ‘Maybe we’ll do a season,’ and then ‘Maybe we’ll do a couple seasons,’ and then I heard some shows go five seasons, and now we’re in season 14, hitting episode 300, and it’s insane! It’s also amazing, our fans have been incredible and they have really made this happen in so many ways.”

“Grey’s Anatomy” airs on Thursdays at 8 p.m. on ABC.