At this point I question the fact that he has a plan, he just does whatever will please Heonguh(?) and by confessing he is both telling on that bossy guy and making it so Heonguh doesn't dislike him for being dishonest. Well at least tat's how I see it.
Why did you turn yourself over??!! I just don't get it but maybe it's all part of his plan.. Fuckk I'm soooo looking forward already..!!