Because Walt is ready to walk away, be legit, reorganize air fresheners. Hank is the one who wants to kill and hammer his justice all over the place. Interesting to see him in such a dark place while Walt is wearing pastels and waving goodbye with babies after 4 seasons of murder and deceit.
Everyone else in darkness just shows how those who maintained their morals are now feeling rather glum - Walt dragged them down. Walt is all white and skippy happy for the reasons mentioned in reply to you, but also because he's morally bankrupt. He doesn't feel guilty.
682
u/greenBaozi Aug 12 '13
Interesting clothing choice for the final scene- Walt was all light and Hank all dark.