I win? Truthfully I have no idea what is going on though their heads in this. Part of me t...

I win? Truthfully I have no idea what is going on though their heads in this. Part of me thinks that Sangwoo has this murder suicide idea and another part of me think he is going though Bum' bucket list before he kills him. I got more possibilities but I don't know if any of them truly fit. Though the last possibility is that he is grooming Bum to take over his work, make bum really attached to him and then get killed himself. Guess this is why we tend not to know what killers are really like because at some point trying to get into their head one gets confused at what they are thinking.