Fck... I have this weird theory, remember the memory Hana suddenly elapsed or something? What if ... She met Jiyeon that night, Jiyeon confessed that she likes her and Baek saw that that's why they broke up bc Jiyeon can't forget about Hana, then Baek got desperate and became obsessed with Jiyeon, whilst the waiter is the culprit for the killing bc he also somehow have hidden anger with Jiyeon, like what if the waiter is the younger brother of the first girl Jiyeon bullied in HS that needs to transfer? Something like that.
It's nice that Hana is able to understand why he did what he did, sure she has the right to feel upset, but it doesn't really help anyone. So it's really nice that she went to him and wants to comfort him even though he technically broke her trust. They can still talk about it after and it's obvious that this is not a normal everyday situation he betrayed her trust in but a difficult time. Desperate times call for desperate measures.
It would be funny if the whole murder thing is really just in Jiho's mind and Jiyoen really did commit self yeet😭 us readers really did put a blame on every person(men) that was introduced to the story 🥴