I think it's because the father is there to say sorry in her stead and beg Doo-joon to give the pink haired girl another chance and not send her into the states. Judging from the chaos that the mister is doing at the counter, it seems like 'that' situation for me.
i can't tell if you're being serious bc the answer is so violently obvious. who else would it have been? we're 60 chapters in. they wouldn't suddenly inroduce another mentally unstable, violent character.
Because...
The that girl ditched her medicine in hospitable...meaning she doesn't wanted to be treated and deepen her obsession...she thinks Do Joon should be hers no matter what costs.
Second...there is no other antagonist crazy enough to crash into a pregnant lady with an intent to kill fearing no consequences except that crazy bitch.
Third....the dad is making a fuss shamelessly I the hospitable knowing that Do Joon and his pregnant wife had an accident. Knowing Do Joon after that favor he probably doesn't want to even see his teacher. Additionally, raising up so much fuss without caring about the couple who are hospitalised without shame literally tells me that he did this for his daughter
WAIT IM SO CONFUSED HOW DO YALL KNOW HAEKIM TRIED TO KILL HER EVEN THOUGH HER DAD WAS ONLY MENTIONED