This is a flashback. it happened when kirin went to Kang MO house and confronted him about the photos and why he was sending letters to his sister. Now we have a full (or almost) picture about what happened that day.
I don't think Kang MO is in love with her... Because he admitted to the head of the club that he did not kill them all because of her it was all an excuse to let out his Dark side. Maybe he liked her has a friend because she was the only one with whom he could be himself.
Yup, that’s what I think too. Thank you <33
You're welcome
Wait, what? I’m lost. I hope he didn’t love her.