Leper's enlistment in the Army had not given him the opportunity to immediately join the ski troops. He found himself unable to cope with the demands, regimentation, and horrors of the Army training, so ran away.
His telegram to Gene, reporting that he had "escaped" and needed Gene was a desperate attempt to reach out and reclaim some little bit of the tranquility and peace of mind that Leper had known with Gene and the others at Devon School. Leper needed to be with an understanding friend - someone who would appreciate how awful the Army was, someone who would understand why Leper had been forced to take the drastic action of going absent without leave, someone who would reassure him that he wasn't "psycho."
In the end, however, Gene was unable to give Leper the support he needed.
Shut up! I don't care! I don't care what happened to you, Leper. I don't give a damn. Do you understand that? This has nothing to do with me! Nothing at all! I don't care!