So—

Seongrok got hard while killing blondie because of the adrenaline rush. It wasn't because he has a kink. That's a normal reaction. Having to kill someone who abused your "girl" is exciting after all. ╮(￣▽￣)╭

Anyway, it seemed like Seongrok killed him because of what he did to Je-oh. It's starting to feel like he wants to kill all of them for him and not because of Ms. Jeon anymore.