i can't get sanwoo's plan. why did he get so mad in bum saying he have felt nothing in kil...

this is only my opinion but i think it's because he didn't want bum to feel nothing. sangwoo said he sacrificed a lot for that moment and basically tried to make bum kill with his own bare hands, so he would find the thrill (is that the word?) that sangwoo finds in it too, that way they're "together forever" (●￣(ｴ)￣●)