"Bonzo"

Graff and the chief of the I.F. military police, General Pace, are having an argument over whether or not to defend Ender from a threat from one of the kids in the school. Petra and Dink warn Ender of the threat, and he already knows this, deciding that the teachers would keep him safe, since he's everything they wanted. After winning his battle the next day, Ender goes to the shower and a group of kids, led by Bonzo, meet him there. He doesn't want to fight him, but Ender realizes that the only way Bonzo'll stop is when Ender puts enough fear into him. Ender hurts Bonzo really badly from the fight in the shower, and Ender feels terrible about it. Later, he wins a battle against two armies, and doesn't even care about it. When he gets back to his room, he gets a sheet, graduating him to command school. Ender is taken back to Earth, and he realizes that he's gotten so used to battle school, that he made it home, and that earth is as strange to him as battle school used to be. Anderson and Major Imbu have a conversation, about how he killed Bonzo and Stilson, and that he entered command school just in time, because the war is nearing.

While reading, I noticed that the fight with Bonzo was just like the fight with Stilson, where he had to unwillingly hurt someone else to defend himself. He wins a battle with the odds against him soon after, and he doesn't even care, because killing Bonzo was the worst event to happen in his life so far. He doesn't care about anything anymore, because he is so depressed from how the way things have happened.