Responses
ngl pretty good theory
At that point he had many reasons to run away. Aside from being threatened, the dude kissed his crush too. It was all or nothing for him to start a new life. But from that, it also makes Seoin feels betrayed. He felt abandoned by his freedom..
Hey, we still don't know if seoin did that or his brother
So maybe Yeongwoon ran away with the money because his father beat him up again, after Seoin's mother went to his house and gave the money to settle everything (the brother beating Yeongwoon) and he took Seoin's advice and never looked back, specially if Seoin wasn't in Korea at the time.