McMurphy Leaving

McMurphy was given the chance to leave several times throughout the drunken night described in the last 40 pages. Why didn't he leave? Why don't he take his opportunity when he was offered it, since he's been on his best behavior so he wouldn't be infinitely committed to the ward? 

It almost seemed as if he had given upon defeating the Nurse, but the Chief realized that the men in the ward were the only reason he had kept going as long as he did. McMurphy made jokes as he was put through electric shock treatment, to keep the men believing in him. He felt responsible for their well being, for helping them become men again, instead of the rabbits they had become under Nurse Ratched's watch. 

McMurphy felt he couldn't leave until the men were strong. He attacked the Nurse in a last ditch effort to revive the men's manliness.

Caitlyn Hines