Honestly after all I have seen, I can bet that Jinwoo really is a psycho, just like Guwon ...

Honestly after all I have seen, I can bet that Jinwoo really is a psycho, just like Guwon said to him, he just doesn't see it yet, because of his partial amnesia, something like he forgot about who he really is, so he thinks that the role he's playing is his real self.
I speculate that he might think that he is normal now, because he acts like normal person should act and feel, by book. I see it in his reactions that are often mismatched to the character that he presents us, he's playing the "good teacher/good person" role but it's sometimes slips. That's why I think he's so set on his stance against violence, but can also move on very quickly without batting an eye as we recently saw.
I'm really interested of what the author id telling us when his eyes get that unnatural green in them.