Because I thought Gyung only does Hyung until he tells Gyung not to sleep with Charlie ┑(￣Д ￣)┍
Hyung caught Gyung doing it with Charlie several chapters back, that's why he got off on the wrong floor when he left after catching them and ended up in the basement where Myoung raped him.
（￣へ￣）thank you sooo much! I never knew it was Charlie
Because in the intro he says kijima Akira, but everyone else calls him miyaji sensei ╮(￣▽￣)╭
(▰˘◡˘▰) (=・ω・=) you da best!