i think sangwoo stabbed himself?
remember he was cleaning so its probably slippery, also in the last panels his feet were kinda twisted as if he was slipping? xD
Wait. Wait. Wait. What if that is what happened. Think about it, what if he stabbed himself to make it look like he was attacked? The cop DID break into his house with out legal permission. And other people already know that the cop is kind of obsessed with Sangwoo, others in his own department think he has issues. So if Sangwoo went to the police about the break in and being "attacked" i'm better the police would believe Sangwoo and say that the cop is carzy
Holy shit your a GENIUS!
If Sangwoo is the one who got stabbed...maybe it is just a part of his plan...and there's not much blood dripping.. Sangwoo planned it that way so that he could disturb the cop..
I think... please dun kill me///