The Butt Room episode in A Separate Peace exposes the conflicting feelings Gene is carrying regarding his actions at the jumping tree. As Gene fights to maintain his innocence, he is also forced to face the consequences of the "accident" and how they might impact his position among the other boys at Devon.
When Brinker presents the "prisoner" to the group gathered in the Butt Room, Gene is already angry with Brinker for accusing him of arranging for Finny's fall so Gene could have the dormitory room to himself. No one but Gene understands that the motivation for bouncing the branch was a much deeper jealousy, which Gene can't yet admit to himself. Gene's anger at Brinker's presentation attracts the attention of the others and he has no option but to play along and hope to change the direction of the inquiry.
I didn't do hardly a thing,...I-all I did was drop a little bit...a little pinch of arsenic in his morning coffee...Oh, you know about the tree,...first I stole all his money. Then I found that he cheated on his entrance tests...then I...What did I do then?...I'll bet you've got a lot of theories. Come on, reconstruct the crime. There we were at the tree...Then what happened, Sherlock Holmes?...Lousy bet...I guess you're Dr. Watson, after all...Enough of this contretemps. I've got to study my French.
As Gene makes the younger student the butt of the joke among the others in the Butt Room, he realizes that the boy now hates him. He also realizes, "For my escape this was a price I was willing to pay." For the time being, Gene has saved face among his peers and been able to quash further questions about the tree incident, at least from others.