After thinking about it for a bit, maybe (just maybe), Yurim is attracted to Soha. If she really hated her, she would have jumped her with her thug friends, like one of them suggested. Even if she's strong, Soha wouldn't be able to resist being ganged up on.
That Soha is "disappointed" in her, the look she gives her when she punches her and Yurim's attitude around Soha, makes me think that deep down she wanted to be acknowledged by her and since it has come to this, she's now bitter because it can't be fixed anymore. But she still puts Soha on a pedestal, even if unconsciously.
Or maybe I'm making things up >.<