Episode 6 is pretty good. Koichi mostly spent time with Mei of learning the people who died in the past. The ending part is getting suddenly insane with the teacher gone mad bringing a knife in class.
I knew it has to be the teacher who kills himself with the knife stabbing through his throat. Koichi's nightmare was a bit creepy with everybody & himself turning into ooze-like.
Actually, I knew the teacher was gonna die this episode. Well, I know who will die next and I know who's the extra person in the class. All I can say is that you'll be surprised.