Patients at the Footy

A doctor at an insane asylum decided to take his patients to the AFL Grand Final. 
For weeks in advance, he coached his patients to respond to his commands.
When the day of the game arrived. Everything went quite well. 
As the National Anthem started, the doctor yelled, "Up Nuts", and the patients complied by standing up. 
After the anthem, he yelled, "Down Nuts", and they all sat back down in their seats. 
After a goal was kicked, the doctor yelled, "Cheer Nuts."
They all broke out into applause and cheered.
When the umpire made a particularly bad call against one of the star players, the Doctor yelled, "Booooo Nuts" and they all started booing and cat calling.
Comfortable with their response, the doctor decided to go get a beer and a meat pie, leaving his assistant in charge.
When he turned, there was a brawl in progress.
Finding his tizzied assistant, the doctor asked, "What in the world happened?"
The assistant replied, "Well everything was going just fine until this guy walked by and yelled, 'peanuts'".