If Yoonseo is really just using her, it only shows even more how awful she truly is and that she might be willing to do anything to get what she wants..
These 4 panels represent Tae Ha and Hae So's respective fears of being abandoned by each other.
Both during discussions of them accepting their fear and being victims to it rather than fighting against it.
The way author focuses so much on him makes me think she will make him the ML or something, he got so many flashbacks and the focus always back to his backstory compared to the others and that annoys me because what's the point of that??