I did not expect that door to close, or that confrontation to happen this early in the game. It just drives home the point that this shit is ending, and that the final confrontation won't be Walt vs Hank, but Walt vs Jesse.

Actually, I think it'll be Walt vs Walt. I suspect that ricin is for himself in the event that he gets caught. Go back to what he told Hank, 2 things stuck out to me: "I'm a dead man" and "You know I won't see the inside of a jail cell" <--- Paraphrasing, but you know what I'm saying. He was speaking in the context of having cancer, which may or may not be in remission by the end of the story, but either way those words felt prophetic.

That scene was magnificent because we saw every version of Walter White in like a 2 minute span. The Ned Flanders schtick, the begging, and finally the threatening. It was like the 5 stage of grief, Heisenberg style.

As far as the cold open, it seems pretty clear to me he's lost everything ('cept dat ricin) and I can only assume that includes his family. That might not mean they're dead, but they seem to be out of the picture in a very final way. I suppose they could be in custody (or being held hostage by some Madrigal goons) and his plan is to liberate them with that big ass gun, but I'm trying not to get too hung up on the theories at this point.