This column contains significant plot details for May 15’s episode of “Better Call Saul,” “Off Brand.” Do not read if you haven’t seen the episode.

More important than the long-awaited unveiling of Jimmy McGill (Bob Odenkirk)’s alter-ego Saul Goodman in Monday night’s episode of “Better Call Saul” is Kim Wexler (Rhea Seehorn)’s muted, incredulous reaction to it. She’s shocked, and not really in a good way; after a few moments, the only reaction she can come up with is “…huh.” She’s not just skeptical but turned off; there’s a little bit of disgust in her reaction, which has a little bit of physical recoil to it.

After two-and-a-half seasons building up to it, “Better Call Saul” nudges Jimmy towards the persona he will become through the conduit of a 12-month suspension from the New Mexico bar. Oddly, the story of how Saul Goodman was born has been a quarrel between brothers about who has the right to practice law — and odder still, why exactly Chuck (Michael McKean) holds the law in such high esteem has not been addressed. Chuck trusts Jimmy enough to help him insulate his house with Mylar and stand guard as he tries to reconcile with his ex-wife, Rebecca (Ann Cusack). But when it comes to using that J.D., Chuck seems to snap — and as we’ve seen in the second season, he will travel to absurd lengths to undermine and delegitimize his younger brother’s practice.

What is at the core of Chuck’s distaste for James McGill, Esq.? That’s been the story of “Better Call Saul” for the last 25 episodes, but as is characteristic of storytelling by Vince Gilligan and Peter Gould, the show has not offered clear answers. Is it merely a territorial spat over the profession, as McKean suggested when we spoke about “Chicanery”? Is it long-simmering resentment over Jimmy’s ease at smooth-talking and joking through the world, up to and including Jimmy’s ease with their late mother? Is entrenched paranoia a symptom of Chuck’s electromagnetic sensitivity — which may or may not be a side effect of mental illness? Or does Chuck hold the legal profession in such high esteem that he feels Jimmy cannot be trusted with it?

It’s not clear if Chuck thinks that the law is just that holy or that Jimmy is just that awful, but neither, from what we’ve seen, is true. The law is still a system used by many for bad ends as well as good, and Jimmy is a flawed person who is capable of acts both selfless and selfish. Perhaps Chuck could argue that the law is black-and-white and uncompromising, while Jimmy is constantly softening boundaries and blurring edges. But even that isn’t strictly true. The law has plenty of gray areas, and Jimmy himself does have a couple of defining principles — “get a lawyer” being among them.

Chuck’s tragedy — and he is a tragic figure — is that he is uniquely encouraging the outcome that he is spending all of his time trying to prevent. The more he distrusts Jimmy and elevates the law — the more he blocks Jimmy from legitimate practice — the more likely it becomes that Jimmy will find a way to work around the system. There is something hateful and patronizing about his efforts that thwart Jimmy’s advancement at seemingly every turn. At the same time, Chuck turns out to be right: He sees how dangerous his smooth-talking brother is, where everyone else sees a lovable huckster. Whatever else is influencing this crusade of his, the frustrating truth is that his concern is justified.

In last week’s “Chicanery,” “Better Call Saul” offered up an example of Chuck’s version of chicanery: Shipping in a bunch of nonfunctional kitchen equipment so that the brothers can try to convince Rebecca that everything’s normal with Chuck. Aside from the plot of the episode, what’s intriguing about that moment is how Chuck’s artifice is aesthetically so different from Jimmy’s; where Chuck opts to dazzle with a version of sophisticated elegance, Jimmy’s tastes run to the cheesier and cheaper. Even as a relatively wealthy man, Jimmy looked a bit like a used-car salesman waiting for his next target, with his multicolored suits and pinky ring. And even at the height of his success, his commercials lacked elegance or artistry. They usually tapped into some form of manipulation or another: Either simple fear, as was the case with the Sandpiper spot, or apple-pie patriotism, as was the case with “Gimme Jimmy.” It’s been interesting, and very predictable, to see how skillful Jimmy is at two-bit advertisement production, showing an admirable facility for improvisation from the Visine tear in “Amarillo” to the waving American flag in “Nailed.” But while Jimmy is very good at producing an effect, he’s terrible at producing an effect that is elevated, meaningful, or beautiful. It sometimes seems like this is the bulk of Chuck’s evidence against Jimmy; after all, Chuck is not above artifice of his own, and used it to quite some effect this season. But it’s the elegance of the con that seems to matter. Even when Jimmy is doing well, he always lacks class.

And this is certainly on display in “You Belong on TV,” a tongue-in-cheek, metatextual, and extremely funny commercial where Jimmy puts on aviators, glues on facial hair, and uses so many star wipes even the local broadcasters are surprised. But in the context of the show, it’s a horribly tragic sequence, where Jimmy, his voice laden with desperation, races through a prepared script that sucks up to the unseen audience without much enthusiasm at all. It’s effective, but in a way that seems to suck the life out of him. Jimmy’s not just a used-car salesman here, he’s a tired one — but too invested in the outcome, and too ashamed of his own downfall, to admit that to Kim.

In the gulf of difference between these two brothers, Kim has been the calibrating point. Chuck and Jimmy have such a distorting dynamic with each other that Kim’s perspective as an outside party feels vital; she legitimates both Chuck’s respect for the law and Jimmy’s good heart. Unlike either brother, her only strategy for getting ahead is working hard.

And every time we’ve seen one of Jimmy’s commercials, Kim’s reaction has been crucial to understanding our own. In “Klick,” when Kim watches the “Gimme Jimmy” ad, the shot is a closeup of her rapt face, with the hovering TV screen over her right shoulder. In “Amarillo,” Jimmy watches Kim watch the commercial, with one long inscrutable look that she doesn’t return. In Season 2, Jimmy seemed amazed that Kim would be interested in his salesmanship — a side of himself he is used to minimizing. But maybe for Kim, the aesthetics of the commercials were irrelevant as long as it played into her own values — principally, that of hustling until the end, no matter the cost.

Then again in Season 2, Kim and Jimmy were pretty unmistakably in love; in Season 3, something has clearly shifted. Jimmy’s great act of love for Kim — securing her the Mesa Verde account through wrongdoing, when her hard work was about to be co-opted — also created distance between them. She actually called her own love for Jimmy “the fallacy of sunk costs,” albeit in a sweetly romantic way.

But in this moment in “Off Brand” where Saul is revealed, the two inhabit the same shot but apparently different worlds. They are both staring to the left of the viewer, with very different expressions on their faces. Kim seems to be waiting for Jimmy to tell her that what she just saw was a joke. Jimmy seems self-deludedly blissful, experiencing a moment of contentment in between the stresses of the day past and assured anxiety ahead.

What happened? Is it that the commercial is finally just truly that bad? Is it the desperation in Jimmy’s voice as he plays “Saul Goodman,” a.k.a. “it’s all good, man”? Is Kim losing her faith that Jimmy is better than what Chuck says he is? Or is it that divorced from the legal profession, Jimmy’s hack sensibilities can be more plainly seen for what they are? It’s kind of funny, that on a TV show that’s a spinoff of another TV show, the climactic moment in a character’s becoming is not just having made a piece of bad television but then watching someone else uneasily watch the bad television. Does making bad TV reveal something about Jimmy, or change Kim’s opinion of him? What about Saul Goodman is so off-putting for Kim?

The essential puzzle of “Better Call Saul” is in wondering if Jimmy would have “broken bad” regardless of Chuck’s actions — and like the original “Breaking Bad,” the slowness with which “Better Call Saul” has unfolded makes locating any one turning point rather difficult. A corollary puzzle is in wondering what exactly makes Saul different from Jimmy for his bellwether, Kim, the one person who knows him and continues to believe in him. There are a lot of possible explanations, and doubtless “Better Call Saul” will offer us more on Kim’s perspective as the episode goes on. But this spells the beginning of the end for Kim and Jimmy. And it’s all a moment of insight reached, of course, through the shared act of watching TV.