Thus:
Han Sooyoung trash talks you but will burn herself out for you in love. Violently so.
Yoo Joonghyuk won't say much but will quietly fight for you and by your side.
And no matter what Kim Dokja says, he will read you & obsess over what you are if you impact him enough.
✿
Han Sooyoung feels a lot, her emotions are intense, and she overcompensates for the discomfort because of the intensity by being overly rude and flippant with the people she feels most for. Still, it is her actions that one should read to determine whether she truly cares or not.