I hope they're gonna kill Bum's uncle. Btw...what if from now they're gonna kill only bad ...

"Kill bad people"? A kill is a kill dude. To some, that chick was "a bad person". It's never ok to kill. This would turn out being some psycho death note or smt

Of course, a kill is still a kill. However, now that you've mentioned it, Sangwoo does have that kind of fucked up mentality, killing people who he thinks is vile, just like in death note. Even Seungbae is fucked up if you assess his "sense of justice". In the end, it's all about choosing the lesser evil, but it's still evil.