So Susan had go to Art class nude and nothing happens after her walking out, like Andre just allows her to quit despite she laughed at the nude model, her punishment should been she had to be the model for the class or Susan should had her Cardigan stolen which would been the more logical way to have continue the story for two so ways to ended,
The First one: Susan would just model for the class, Which would would got a chance for payback
The Second way: Susan had to streak home (Mike probably drove her) without getting caught until she was in Wistera Lane then she would be compete embarssed.