What happens when Armpit encounters Felix and Moses coming back from his speech exam?

On his way back from his speech exam, he's confronted by Felix and Moses. Their confrontation reveals a conversation in which Armpit has told them they'll get the letter on Monday. Moses tries to beat Armpit into handing the letter over right away. Armpit, toughened by life at the correction center, fights him off. Their fight is interrupted by a cry from a passing limo driver that he's called the police. Felix and Moses run off, and Armpit runs home.