I get what he's doing ; he hurt (unintentionnally) Yeonwoo and probably that the other asshole told him stuff while beating him. So he thinks that getting away from Yeonwoo by being hurtful will help him, but that ain't it chief
sure their friendship isn't the most healthy, but completely cutting ties without clarifying anythin isn't right, especially with how low Yeonwoo's self-esteem is. Guess we will see them rekindle in the future chapters and at the same time have a healthier relationship