In chapter 9-12, how did John McNab confirm his reputation as a bully?

This question is a bit odd because John McNab does not show up in chapters 10-12. He does confirm his status as a bully in chapter 9. The chapter begins with narration about how McNab is still angry about Maniac humiliating him at the baseball field. In McNab's opinion, if he can't strike somebody out, beating them up is the next best thing. McNab decides that this is what he is going to do, so he gathers up a few of his Cobra gang member buddies, and they go hunting for Maniac. They discover him running on the train rail, and they chase him with the intention of beating him up. Maniac doesn't want this to happen, so he runs away. He runs to the other side of Hector street, and McNab thinks that Maniac is going to end up just as beat up over there as he would have at the hands of the Cobras.