Chief Bromden isn't really crazy, he's having psychic visions of one or more parallel universes that have been conquered by The Combine.
Obvious, really. Bromden's first name is Taylor
He was brought in because the orderlies thought he was delusional for seeing ghosts. He was in before Ratched and the New Orderlies came and pulled on the deaf-mute act for them. He later escaped and took refuge in Canada, before Tangina called for him.McMurphy isn't really dead, He's Just Hiding.
The ending was all one final Batman Gambit so he could get Bromden to lift the sink and break the two out. Because he sees that Chief is the only one strong enough to lift the sink. The final shot wasn't Bromden running in the woods but McMurphy, following him. Bromden is Holden Caulfield.
At one point in Catcher, Holden fantasizes about pretending to be a deaf mute. Coincidence? Mccmurphy is reincarnated as The Joker.
Think about it: besides both being played by Nicholson, Joker has a love of fun, albeit the psychotic sort. Plus, in Killing Joke, Joker said, regarding his past, "sometimes I remember it one way, sometimes another. If I'm going to have a history I prefer it to be multiple choice." What if the reason his memories are so fragmented and inconsistent is because of the lobotomy he received as Mccmurphy? Plus, it would explain his sympathy for the lunatics of Arkham, because they remind him of his fellow patients at the institution.
