A review of tonight's "Breaking Bad" coming up just as soon as I use up every cleaning product in a 50-mile radius...

"The bad way to remember you would be the way you've been this whole last year. At least last night, you were, you were real, you know?" -Walter Jr.

It's funny: "Breaking Bad" is a show about a chemist, who, near the start of the series, told his students that chemistry is the study of “growth, then decay, then transformation." And for a very long time, it seemed that the lives of Walter White and Jesse Pinkman were constantly shifting between those three states. But the dynamic between the two of them - both their relationship and the way they came across to the audience - seemed a bit less in flux. There was a notable transformation between the start of the series (when Walt seemed the sympathetic suburban dad, and Jesse the skeevy idiot) and early in the second season (when Walt started to embrace his role as Heisenberg and became an overbearing bully, while Jesse started to become the one we felt bad for), and that's more or less how the show has treated them in the years since.

The fight at the end of last week's episode blew up their relationship but good. And in the wake of that, "Salud" suggests that their respective roles might be reversing once again.

The more apparent shift comes from Jesse, who does one hell of a Mr. White impression for all the chemists in the Mexican equivalent of the Super Lab. He didn't have Walt to coach him, but he's spent the better part of a year (in the show's timeline) studying this guy, seeing how he treats his inferiors (which in Walt's eyes is everyone), how he carries himself and the rest, and he pulls it off beautifully. And while it's a performance to save both his own life and that of Gus and Mike, when the violence starts after Gus murders Don Eladio and most of his capos, Jesse joins in the fight and reacts without thinking to the sight of Mike being wounded, turning and quickly emptying a clip into the offending gunman. (Those first-person shooter games definitely came in handy.) In the past, Jesse avoided having to kill people, and struggled mightily with both the act of murdering Gale and the aftermath. Here, it's an instinct, just as it's been for Walt when he's become Heisenberg in the past. Jesse lights up a cartel gunman, pulls the injured Mike into the car and peels out of Eladio's compound, playing the badass hero for others in the way Walt has for him in the past.(*)

(*) And given both the schism with Walt last week the way Gus and Mike fight for him here, and the fact that Jesse saves them both when he could easily kill them or leave them to die, for the moment I don't think there's any question about where his loyalties lie. As with all things "Breaking Bad," the situation remains fluid, but right now Jesse seems to be on Team Gus & Mike.

Walt, on the other hand, spends the episode trying to heal from the physical and emotional smackdown Jesse laid on him at the end of "Bug," and there are suggestions that he might finally be realizing that he's disappeared far too deep into the role of Heisenberg, and that it might be better for everyone if he gets out of it.

Of course, much of this regret is fueled by painkillers and booze, and as we saw last season in "Fly," narcotics have a way of loosening both Walt's tongue and his sense of guilt. He whimpers to Walter Jr. about how sorry he is - in an acting moment that would seem astonishing if we hadn't been watching Bryan Cranston in this role for the last four years - and his tears and pain are so genuine that it's clearly not just part of his cover story about gambling(**). He may be conveniently exploiting his emotions to sell the story (and again be an awful parent), but in that moment, he feels terrible about everything he's done to his surrogate son (whom he confuses with his real son as Walter Jr. tucks him in), and possibly about everything he's done as Heisenberg, period.

(**) Bryan Cranston is a great actor. Walter White is not.

Of course, in the sober light of the next day, he tries to back away from what he's already begun to view as a moment of weakness, but Walter Jr. won't let him.(***) Walt delivers a long monologue about his one memory of his father - and it's a piece of backstory that explains quite a bit about Walter White's pride and fear of being seen as weak, dying slowly in a hospital, being cared for, etc. - and explains that he doesn't want Walter Jr. to view him that way. But in Walter Jr's eyes, the crying Walt is much closer to the dad he grew up knowing than the secretive, angry, edgy troublemaker that he's gotten a glimpse of this past year.

(***) For all that we joke about how Walter Jr. is just there to eat breakfast (and note that when Skyler offers him a choice of meals, he goes with pancakes), this was an episode that gave RJ Mitte a whole lot more to do emotionally, and he was really, really good. The kid's been able to work alongside and watch Cranston for a while, and he's clearly picked up a few things. His tearful reaction to seeing his father so battered and sad and apologetic was very nicely done.

We go back and forth a lot in discussing this show about which version of the lead is the real man: Walter White or Heisenberg? Walter Jr. wants to believe it's the former; Walter Sr. the latter. Walt has seemed on an inexorable path towards becoming Heisenberg 24/7, and he could very easily still get there. (Both Jesse and Walter Jr. have shamed him in different ways over the last two weeks, but Walt's default mode is generally to rebel against those kinds of feelings.) But as Jesse gets deeper into the drug game himself, and more confident and less apologetic about the bad things he has to do to survive, wouldn't it be awfully interesting to see the two men forced back together with their roles very different from even a few weeks ago?

Either way, this was another fantastic, fantastic episode. Season 4 is on a real roll as we head into these last 3 episodes. Damn.

Some other thoughts:

• For all the times that Jesse and Walt have plotted to poison someone with ricin, it's Gus who actually succeeds in solving a problem through poison. I wondered at first about the pills he was taking right before Don Eladio came out, but either it was an antidote in the event he had to take the stuff, or simply something that would make it easier for him to vomit it out later. And, just as in the dressing/undressing sequences from "Box Cutter," I love watching the precision of Gustavo Fring, who is neat and machine-like even when he's preparing to make himself puke up some poison in the guest toilet of his archenemy. So Gus both gets his revenge and, presumably, throws the cartel into so much disarray that they'll leave him alone for a good long while. Last week he got to emulate the Terminator with the way he walked out into the sniper's field of fire, not even flinching at the bullets, while here he pulls a Westley from "The Princess Bride" and pretends to be much more hearty and able-bodied than he actually is to first fool Don Eladio, and then to intimidate anyone in the hacienda who's still thinking of coming at them. Third incredible climactic sequence in a row this season, starting with that great shot of Gus standing over the same pool where his life changed forever 25 years before, now a very different man but one with a long memory.

• I was much less a fan of the Skyler/Ted storyline. I know it's a cliched dig to compare any bit of bad TV writing to "Three's Company," but in this case, this literally was a "Three's Company" plot: there was an episode where Janet and Terri want to secretly give Jack money to help him get out of debt, and pretend that he's won a radio contest, only for him to spend the cash on a new leather coat. There could be an interesting payoff now that Skyler has come out and told Ted that it was her money - albeit not where/how she got it - but those scenes were definitely the least compelling this week.

• Good to see Carlo Rota (Morris O'Brian from "24") as the snooty cartel scientist. Rota's one of those actors (like Lou Diamond Phillips or Tony Shalhoub) who gets treated as variably ethnic by casting directors.  

• Other than the plot convenience of the messages playing loudly throughout the house even as they're being recorded, why are Walt and Skyler still using answering machines instead of voicemail?

• Lots of talk about various car features in this episode. In fact, if Chrysler hadn't discontinued the PT Cruiser last year, I would take Skyler's scene in the driveway with Walter Jr. as product integration. Instead, both father and son are now driving cars that aren't produced anymore.

• Playing the role of Shovel Cam this week will be Bikini Bottom Cam!

What did everybody else think?

Alan Sepinwall may be reached at sepinwall@hitfix.com