Why do you think Gene reacts so violently to what Leper is relating to him?

Gene goes to see Leper at his home in Vermont, and Leper is definitely changed; he is very unpleasant and bitter with Gene, and seems to have been scarred in some way by his time in the service. Leper accuses Gene of causing Finny to fall out of the tree, and reveals that he left the service because he was about to be discharged for mental health reasons. Gene gets angry and attacks Leper for his comments, then apologizes and is too embarrassed to leave immediately. After lunch, Leper and Gene go for a walk, and Gene sees that Leper really has cracked up. Leper talks nonsense, and somehow it affects Gene, who yells at Leper to stop talking, and then runs away when Leper won't.

Why Leper'sr talk disturbs Gene so much is not made clear at all; Gene doesn't say why he is so incredibly upset at it, though presumably it has something to do with him identifying with the feelings that Leper is expressing. Still, the prose in this section is rather murky, with the only reason that Gene gives for not wanting to hear it is that it has "nothing to do with [him]" (143). Does this mean that Gene feels responsible for what happened to Leper? On the other hand, how could he feel any responsibility, not having been there when Leper started going crazy, and after being a better friend to him than most of the boys at the school. Does Gene feel that he too is going crazy, which is why he doesn't want to hear it? Or is Gene simply being callous, and doesn't want to help Leper out any more? Because the motivation for Gene flipping out and running away is anything but clear, his reaction doesn't have the same power that the prose clearly intends it to have. Gene says that he "didn't want to hear any more of it. Not now or ever I didn't want to hear any more of it. Ever" (143); the repetition emphasizes his sentiments, but since it is hard to figure out why he is acting like this, it is impossible to empathize. Gene's story gains most of its emotional impact through the empathy he helps his reader to feel with him, but when it is difficult to find a way to empathize with him, this emotional impact is lost.