SPOILER ALERT: Do not read if you have not yet watched the “Station 19″/”Grey’s Anatomy” crossover that aired Jan. 23.

“Station 19” and “Grey’s Anatomy” kicked off the start of their official combined universe with a two-hour block that began with the third season premiere of the former Shondaland series. In the episode entitled “I Know This Bar,” there was fallout from a car crash as well as flashbacks to what what going on with the firefighters while the series was off the air.

Then, in the second hour, “Grey’s Anatomy’s” 10th episode of Season 16 (“Help Me Through The Night”) was rooted in the present as a number of doctors — successfully — fought to survive after that car crash; Bailey (Chandra Wilson) grieved the loss of her unborn child and Teddy (Kim Raver) and Owen (Kevin McKidd) took a big step forward in their relationship.

Here, showrunner Krista Vernoff breaks down the big moves on both shows.

“Grey’s Anatomy” hasn’t featured a major character death in a number of seasons. At this point in the show’s run, what is the debate amongst the writers and producers about when that device is best used?

That question makes me laugh because, for sure, it was a signature of “Grey’s Anatomy” for many years to kill off characters. When I came [back] in Season 14, you’re looking at how do you surprise people anymore? And it continues to feel like the more surprising thing to not kill them. I often say to the writers, “Then, when we do one day, it will be genuinely shocking.” With this big crossover event, I will say that there was, in initial discussions, the intention to have someone die. But what happened is that we realized, as we were breaking [the season of] “Grey’s Anatomy,” that Bailey was going to lose her baby. And we realized as we were breaking the midseason finale, that we weren’t going to have time to properly process that loss. So as we were writing the [midseason] premiere of “Grey’s Anatomy,” the loss of Bailey’s baby felt so potent as a loss, that it felt if we were going to kill someone else, it almost felt like a hat on a hat. It felt like, let’s grieve this baby. That scene [where she grieves the miscarriage] — I weep when I watch that scene. I went up and watched the editors cutting it, and they were cutting it through tears. Chandra is so extraordinary in that scene, and every person I ever know who’s lost a baby needs that scene. And that loss needs to be felt as deeply as any other character we might have killed. For us, Bailey losing a baby 16 seasons into the show, that feels like a death. And I wanted to give it its due. I didn’t want to step on it with, “Oh, and that intern died, too.” So it felt like the better storytelling.

Can you reveal who you were planning to kill off in the early discussions?

Everybody in that episode, at some point, was on the chopping block. The amount of times that we’ve decided we’re killing characters, and then we’re like, “No, let’s change it” — it would drop your jaw. And you’d be amazed at how many people have been on the board for weeks; we come up with different codes that mean that character is dying. And then we’re like, “No.” So there’s no one person. There were a lot of conversations about who might die in that bar, from both casts. At the end of the day, Bailey’s baby felt right.

Owen and Teddy are now engaged, but it came after they got a fair amount of external pressure about the status of their relationship. And there’s also the fact that his ex-wife, Amelia (Caterina Scorsone), is no longer sure about the paternity of her unborn child, while Teddy’s ex, Tom (Greg Germann), seemed upset at the reveal. What’s next?

What Tom is feeling there is primarily is terrible pain. There is nothing clean or easy about this particular engagement at this moment, because now Amelia is keeping a secret. She’s not just keeping it from Owen and she’s not just keeping it from Link — she’s keeping it from herself. We don’t know who the father of that baby is. And that is a big messy story moving forward with the season. For sure, Tom’s feelings for Teddy, which I think are not entirely unmutual, are a factor moving forward. We talk about Tom and Teddy and Owen and Amelia as a quadrangle, and that story is certainly not complete.

Jo (Camilla Luddington) seemed attached to the idea of being a Safe Haven volunteer and made a comment about not being a mother yet. How much will the show be pursuing Jo’s maternal instincts, especially now that Justin Chambers, who played her husband Alex, has left the show?

For us, Jo taking that baby felt less about becoming a mother than about trying to mother her own inner child. It felt like she was holding a baby In her arms who represented her as a baby, and she was trying to find some healing through being a safe haven volunteer and holding that baby and beautifully, just didn’t want to let that baby go. For me, that story was just another step on Jo’s healing journey.

So it was just a couple of episode arc versus being a significant part of her immediate future?

I don’t know for sure about the future. But in this moment, yes, that isn’t the story that she’s pursuing.

Maggie (Kelly McCreary) was blindsided by the reveal she’s being sued by her uncle for the wrongful death of her cousin. How will she be coping?

Maggie is going through a really difficult thing that most surgeons go through in their intern year. The writers’ room, we talked a lot about how Maggie is a genius. She’s incredibly good at what she does. Has she ever been through the death of a patient that may be in some way due to her error? And we realized we hadn’t really seen it onscreen, which meant it probably hasn’t happened. Which speaks to her seeming, sometimes, like almost like an immaturity. Kelly McCreary has often asked, “When does Maggie grow up a little bit?” And for us, this answered that question of, “Oh, she hasn’t been through the kinds of losses and failures that people who are less good go through.” So that was an exciting thing for us to give the character and to give the actress.

We’ve seen Bailey grieve her miscarriage, but her husband Ben (Jason George) was mostly concerned about his wife. How much will “Station 19” be exploring his loss?

What I love about the way we’ve handled this miscarriage is that we’ve kept that loss alive on both shows throughout much of the season. So the people I know who’ve had late stage miscarriages and some of the people I know who’ve had early stage miscarriages, it’s not a thing that just is felt briefly and then gone. It’s an ongoing loss. And there’s an ongoing grief. And I think that sometimes that’s misrepresented in television. It’s done in one episode and never mentioned again. We came at it differently for both of those characters. They’re both feeling it in different ways and discussing it and having various reactions to it throughout the season.

Pruitt (Miguel Sandoval) is keeping his cancer quiet for now, and given the tenuous relationship with his daughter, Andy (Jaina Lee Ortiz), it feels like a ticking bomb. What’s ahead there?

Pruitt is a big story this season on “Station 19.” We tried to tell it differently than the cancer story had been told in the past, and I think we succeeded. It allows the characters to go deeper. Andy has to grow up more and Pruitt has to face his mortality in a very real way.

There were also two different kinds of break-ups: Andy and Sullivan (Boris Kodjoe) imploded over career aspirations, while Maya (Danielle Savre) bluntly dumped Jack (Grey Damon). Is there hope for either couple? And would Andy and Sullivan’s relationship even be appropriate at this point?

It’s not appropriate, but appropriate doesn’t always make great TV. [Laughs.] For sure, we’re exploring the dynamics between Andy and Sullivan, which are really complicated. That’s exciting as a storyteller. Maya and Jack — the way that Maya breaks up with him is so brutal, we’re exploring that as a character trait. We’re really looking at Maya as a character this season and what makes her tick. [It’s the same for] Jack and all of the characters.

We are leaning into a flashback motif this season where we’re looking sometimes at just a couple of years ago for the characters and sometimes at their childhoods to understand how they became the people that they are, why they became firefighters. So we’re doing some really exciting character work and and two of the characters that I think we’ve done a beautiful job illuminating in the early episodes are Maya and Jack.

Vic (Barrett Doss) seemed to move on from Ripley’s (Brett Tucker) death fairly fast, especially in light of her relationship with “Grey’s Anatomy’s” Jackson (Jesse Williams), but the premiere had a poignant scene where she expressed how deeply she had been grieving. Was that a turning point in this recovery for her or is this the start of her being more open about the impact of the loss?

We’re letting both of those things coexist. We are seeing a lighter version of her and we’re acknowledging how much she’s been through. That is a joy for me. [Doss] is incredible, and she brings great emotional depth; she [also] brings lightness and joy and laughter. It all coexists. We’re telling a story about grief that shows what I have experienced to be true: that ongoing grief intermingles with all the joy of life in a way where, often on television, grief is depicted as a dark, dark journey and then you come out of it and you can have joy again and then the grief isn’t really touched on a lot. And Vic is having both: she’s having grief for Ripley and she’s having a new relationship. She’s having her feelings, her sadness, her tears, which allows her to also have a lot of laughter and joy and light and sex and fun. It’s all happening simultaneously. It’s really one of my favorite things we’re doing.

Is there anything else that can be teased about what’s ahead on “Station 19” or “Grey’s Anatomy”?

The first few episodes of “Station 19” are kind of dark and intense, because that’s how we designed them. And then when you get to Episodes 4 and 5, more joy and more light is coming in. These characters, we’re going deeper and deeper and deeper. I really just want to invite everyone to come on that journey. I think fans of of the first few seasons of the show, it may shake them up a little because it feels a little bit like a different show stylistically. But these characters are the characters you’ve fallen in love with. And we’re going even deeper. I encourage fans of “Grey’s Anatomy,” who’ve maybe never come to “Station 19,” to come check it out because Bailey is recurring on that show. And Jackson is recurring on that show. And it’s an exciting fun show unto itself. I don’t want anyone to feel like they have to watch both hours, but that they get to.

“Station 19” airs Thursdays at 8 p.m. and “Grey’s Anatomy” airs Thursdays at 9 p.m., both on ABC.