So the part about having each other's backs (why I oughta...), says Walt, is something they should keep in mind, "as we go forward." Jesse's head kind of perks up at that, pulling him out of his shame spiral for the moment. What exactly does Mr. White mean by that? See, Jesse, lacking the self-awareness that he's on a TV show, doesn't realize there are still 15 episodes to go and thus re-starting the meth business is pretty much a foregone conclusion. He's still under the impression that "getting out with our lives" is a possibility.
Cut to Mike's home, with the telltale "drawing by granddaughter posted on a fridge full of beer" accoutrements. In my favorite attention-to-detail touch of the week, Mike retrieves a bottle of beer AND an Ensure from the fridge as he settles in to watch ... I'm going to say The Caine Mutiny, but I can't swear to it. File that one away for thematic resonance, if that's the case. [Note: Turns out Vince Gilligan is a fan.]
Ideally, Mike would be left alone to drink and tube and grimace at his still-healing chest wound, but he gets a knock at the door from Walt and Jesse, which he answers grumpily but without specific objection. Walt's there to offer a brand new three-way partnership in order to start up the meth business anew. After all, he says, there's a market for their product out there. It's been coming to this for a long time, but we're finally, officially at the point where Walt's "I have to" justifications for remaining in the business have all disintegrated and he's finally just saying "there's gold in these streets, and I plan on getting the biggest cut of it I can." He tells Mike that he and Jesse have the cooking aspect of it down, but they need Mike for things like distribution, support, and logistics. For one thing, they need a steady supply of "precursor" to get started again. He allows that the profits will be smaller at first, but each one of them will be getting a larger cut now, as owners. Mike doesn't hesitate much before delivering a "Thanks but no thanks" to Walt. Unlike last week, when Jesse (in my opinion) used the sway he has with Mike to get him to comply, he stays silent. Instead, Walt makes a dispassionate plea for putting personal differences aside and making a smart business decision. But Mike plainly says that Walt is trouble. "The kid here doesn't see it," he says, but he knows Walt is a time bomb, "tick-tick-ticking," and he has no intention of being around when he goes off. Walt, again swallowing whatever annoyance of frustration he's feeling, says to sleep on it, maybe reconsider in the morning. This is all shades of Gus after he made Walt the offer to join the Pollos team. He holds his hand out to Mike, who -- eventually, reluctantly -- shakes it.