Just speculation but I think Walt finds out Hank knows who he is and that's why he takes it on the lam.
I don't know if they want him to be re-humanized, though. They have been making Walt more and more unsympathetic as the show has gone on. They don't seem to be giving him any moments where he becomes sympathetic as they did with Tony on the Sopranos and Don on Mad Men. That doesn't seem to be the case with Walt as of yet.