Yes, they are rivals. Of course. But who said that they are forbidden to sleep with each other? Without obligations, of course. With jealousy and possessiveness. We are well aware that this "no strings attached" clause is a lie. Even now, Hwang is not holding back from his games. They are at his apartment as always after lectures at the university. He kisses her cheek a few times, and then buries his face in her neck and mumbles.

"If I leave a hickey, will you come up with an excuse for your friends? Or are you going to tell them that you're only fucking with me?"