Responses
The “you’re so fucked” part is him saying that he’s just gonna make him fall in love with him like he did him. His delusional thinking of that somehow being “revenge” he’s lost. He can’t do anything malicious even if he wants/believes he is.
I still think he's going to get back at him somehow tho, because Heejae doesn't seem to trust Seyeong that much at the moment, if not at all. He might like him, but I doubt that'll make his "pissed off" state go away
Damn, don't you dare hurt Seyeong now that's you've made him love you. He's as insecure as you are ╥﹏╥