By chapter 11 of A Separate Peace, Leper Lepellier has become a significant character because of his involvement with the war. Leper was the first of the group to enlist in the Army, but it was not what he imagined, and he left without permission. The reality of Leper’s situation brings the war home to Finny, who finally admits that it is really happening. When Brinker convenes the group of boys to discuss what happened on the tree branch the day that Finny fell, Leper comes to the Assembly Room to provide his version of events. Many unusual features of his speech make it clear that his mental state is fragile. Finny grows upset and, repeating that he doesn’t care, rushes out of the room. The other boys hear him fall down the marble stairs. In the next chapter, it becomes clear that he is very seriously injured.

In the earlier chapter, when Gene describes what happened the day that Finny fell, he is vague about his actions. When Brinker suggests that Leper come to the court-like inquiry that he has convened, Gene is nervous, because he imagines what Leper might say. By this point, he has already spoken with Leper, and he thinks that Leper has suffered a mental breakdown. While Finny had been steadfastly maintaining that the war was a fabrication or hoax, the news of Leper’s difficulties in serving somehow convince him that the war is real.

Leper’s version of events on the day that Finny fell reveals his precarious mental state.

I could see both of them clearly enough because the sun was blazing all around them… and the rays of the sun were shooting past them, millions of rays shooting past them like—like golden machine-gun fire…. The two of them looked as black as—as black as death standing up there with this fire burning all around them.

As Brinker presses him for a precise, realistic description, he repeats this vision and then grows angry with Brinker. Insisting, “I’m important,” he conveys his understanding that Brinker has always underestimated and patronized him. At that point, Finny announced that he did not care, shouted at Brinker, and ran crying from the room. Gene soon hears the “general tumult” as Finny falls down the stairs.