
After this chapter, I want to clarify the punch scene.
1.) Sangyoon (older bro) didn't know that Seongyu (blonde) has been a total bitch since a decade ago. In all likely hood Seongyu has only ever shown his nice side to this brother.
2.) Sangwook (younger bro) has definitely seen Seongyu bully Woojin before, and has a personal vendetta.
The older bro probably gave Seongyu the benefit of the doubt when he pushed Woojin that it was maybe an accident. When you're friends with someone for a long time, you don't want to assume they're being malicious on purpose.
The younger bro knows Seongyu definitely did it on purpose, hence the punch. Regardless how long it has been, he believes Seongyu is still the same asshole he was before (and he is), so he went straight in for it.
Only now did anyone actually tell Sangyoon about Seongyu. He doesn't make rash assumptions overwhat Sangwook tells him, but instead calls his old ex/friend(?) to confirm things. Which is what an adult does---
OMG....DONT CLIFF RIGHT THERE
im screaming