This is actually really thought-provoking and I think you make some good points regarding Joo Hawon trying so hard to survive because he has worked so hard to be free for so long. it's hard for me to know what I would do in this situation, since I have never been in anything remotely close to this, but I would hope to be a fighter like Joo Hawon.
I think because MC grew numb to a lot of awful stuff, he blocked off a lot of emotions and doesn’t find most stuff disturbing enough for him. I mean, he is in a constant state of flight or fight, so he doesn’t have time to process or feel emotions, which is keeping him alive. If he were to sit down, do nothing and think then yeah… it can get bad.
On top of that, he has a childhood friend he cares deeply about, so that’s another reason why he is still alive and trying to get a better life.
i know it's easy to say you'd rather kys if you were in his position, but being a survivor all his life i imagine that concept just shatters everything he had worked for. i'd definitely want to survive, but i know i'm not strong enough to go decades living like a prostitute & a punching bag for something i didn't even do. kms could even be a last resort for an escape & revenge towards that fuck face. i guess the question is what are you living for?