This event allows McMurphy finally to win his bet with the other patients that he could make Nurse Ratched lose her cool and get angry. Even though he manages to win a vote to watch the game, Nurse Ratched refuses to let him, turning off the power to the television when he turns it on and sits down in eager anticipation. However, even though she thinks this will seal her victory, McMurphy's response takes her completely by surprise and results in her losing her temper:
To tell the truth, he don't even let on he knows the picture is turned off; he puts his cigarette between his teeth and pushes his cap forward in his red hair till he has to lean back to see out from under the brim.
What finally makes Nurse Ratched explode is when the other patients come and join McMurphy "watching" the game, even though the screen is turned off. Bromden, bemused, observes that if anybody entered the room at this stage they would not be able to tell who was "mad" and who was "sane." This is such an appropriate way for McMurphy to get to Nurse Ratched because it allows him to challenge her authority and show that he is an individual who will not be cowed or shaped by her manipulations.