Spoilers.
As soon as I saw Walt open Mike's go bag with the gun on top, I had a bad feeling Walt was going to kill him. Such a "peaceful" ending to an episode. A moment of silence for one of the show's best characters. Since Half Measures, he has been glue for this show. I don't know that there's much to root for now. We see how Walt is alone. His scenes with Todd are so empty and bittersweet. He really is estranged from everyone. Todd is simple. I was reminded a bit of Of Mice and Men with this ending, though in hindsight it doesn't really fit. Just the atmosphere and the "let me die in peace" line rang true. I guess, though, as soon as we saw the huge deposit box of money for his granddaughter, we could pretty much assume Mike was through -- even before the go bag.
Walt has very little street smarts and his ego has gotten far out of control. We've all said this episodes and episodes ago, but it comes more true with each passing event, and each mistake he makes where he narrowly escapes, masquerading as luck and ingenuity. Genius in science doesn't equal genius in cause and effect, in human relations, and that of course is Walt's prime failing. He's horrible at reading people, and knowing his place in the hierarchies of society. There's a bittersweet taste going into the final episode of this season. Mike's gone, Jesse's out, his wife won't talk to him, and he never talks to his son. It's clear now how he gets to where he's shone at the beginning of the season, but what else is there left to root for?