Bob broke the drum because he hit it so hard that it bashed. This is what happened.
Mrs Jones: Ok now, Du Lay Lay, you are playing an A. Do Vanilla and Di Sohfie, a high G. Aden, an F, and Magna, a C. Bob, you will play boom, 234, boom, 234, boom, boom, boom boom, chi! Ok?
Everyone: yes!
They start playing and bob breaks the drum. He poos on Mrs Jones' face when she asks him to pay for it. Then be runs home. Well, by car.