Nurse Ratched's authority over the inmates at the ward declined as McMuphy's influence increased. The men on the ward look up to McMurphy like they were his younger siblings. In part 4, Nurse Ratched tries to demolish that influence by revealing the income of the inmates, all but McMuphy's showed a steady decrease. Harding jump to McMurphy's defence saying that they were always told by McMurphy what his intentions were. Another attempt, by the nurse, was having all those who attended the fishing trip to be cleaned. During this event McMurphy and Chief get into a fight with the black boys who tried to forcefully wash George. Afterwards, both men were sentenced to electric shock therapy in Disturbed.
The respect for McMurphy has grown in his absence which forced the Big Nurse to remove him from Disturbed. With help from Turkle, the guys have an orgy with Candy and Sandy. They even plan an escape for McMurphy which unfortunately falls through. Nurse Ratched does her own investigation and see Bill with Candy and sends him to Doctor Spivey saying she was going to tell his mom. He kills himself along the way causing McMurphy to fly into a rage and attack her. She returns a week later and orders a lobotomy for McMurphy putting him in a vegetative state. The man who always stuck by McMurphy, Chief Bromden, puts his friend out of his misery by strangling him and then makes his escape by throwing the control panel through the window.