Oh she's down so bad and doesn't even know it. I think Ji-Ho is just now considering the possibility that she might be attracted to Woo-Hui in a more-than-friends sort of way, because Pink hair brought it up. So now she's struggling with the fact she supposedly loves Pink Hair, but also might have feeling for her straight best friend, and she doesn't wanna lose that since for all they know Woo-hui is only interested in men (especially after that sucker punch). So yeah, I get why she was acting like that. Your best friend who you might have feelings for and is looking super hot but is going on a date with a man, and you don't have any right to tell her not too because you're sleeping with someone else anyways, and she's straight so it's not like it would work out anyways (unless..?)