1x7 - Cinderella at 2AM

While Yoon-seo and Seong-min seem to be getting closer, Ju-won becomes jealous and resorts to Si-won's advice of turning on his belligerent side. His sudden demeanor confuses Yoon-seo and frustrates her, angering her. But when she sees Ju-won with another woman, she is shocked by how flustered it made her.