Why did Leper escape from the military?

Leper escaped from the military before they could give him a Section 8/ meaning he didn't have all of his mental capacities.

Leper reveals that he left the service because he was about to be discharged for mental health reasons. Leper's tale is supposed to stand for what happens to innocence when it is suddenly overwhelmed by experience or reality. Leper quickly found out there was no glamour in the army. He couldn't handle the gruff authority figures.