Gene is a complex guy. He's great friends with Finny, but he's also really jealous of how everything just seems to fall in place for Finny. Gene works hard at school and sports, yet Finny often does better than him with seemingly less effort. After Finny's fall, Gene is partly glad that the playing field is a bit more level; however, Gene also feels guilty about having caused the accident, and he feels guilty that a small part of him is/was glad about it.
Gene's guilt manifests itself in a couple of different behaviors. One behavior is that Gene tries to honor Finny's athletic desires by letting Finny train him. Gene partially feels as if he can work away his guilt by succeeding in helping Finny obtain his Olympic dream in one way or another. Another behavior of Gene's is the one that I appreciate the most. Gene attempts to tell his friend the truth. Gene feels terribly guilty about the accident, and he wants to come clean about it. Unfortunately, Finny is incapable of considering that people might not always have completely good intentions toward other people. Finny flat out denies Gene's confession, which then forces Gene to begin lying to himself and others about his role on the tree branch. Part of that lie is Gene's continued efforts to make it appear that he and Finny are every bit the great friends that they once were. Eventually the lies and suspicions begin to pile up, and they come to a head at Gene's mock trial. The trial isn't successful at solving any friendship problems among the boys.