Earlier Se-mi was talking to you, it started casually but then she started trying to flirt not knowing you have a girlfriend. Before you could back down and say you're taken, Saebyeok saw you two, looking up and down with a stoic expression and then leaving without saying a word.

At the time you didn't know she was jealous so you didn't mind. But when you came back to sae she was "ignoring" you, not completely but she was only doing small talk and seemingly more contemplating than usual

"Out." She takes all the blanket for herself - as if she's the only one sleeping there tonight - and turns her back to you