Was Jongwoo already insane

I feel like even if people here made him go crazy and insane however, he might be in denial from the first place. In military flashbacks he seems to discover his insanity too. 

Maybe they played role in him realize that he is indeed insane, maybe they didn't have a much impact on him going crazy, maybe he was just insane from the beginning and he just didn't realize it yet.

Moonjo might have saw it in him and decide to let him realize the way he is as crazy as him.