It’s been a while so I think I’ve forgotten but why was ISU blocked and why is Sihyeon...

idk if its how i remember it but i interpreted it as isu being on the sidelines while og sihyeon suffers and being a trauma inducer sort of response for the mc and so he doesn't want anything to do with him

plus the fact that og sihyeon and him knew each other somehow that not only mc doesnt really remember but daejun couldnt dig up anything about it which means sus sus much sus

Thank you so much