Yamamoto is definitely the real problem. She is an insane chunni after all, who gets counseling from sensei several times. It's a wonder why he continues to try to have her respond to him in anything other than chunni language. I'm surprised it only took until after exams for Tanaka to recover from the torturous studying she went through.
I hate to say it, but Lily getting annihilated by Tanaka's saliva was one of the best parts of this chapter. RIP Lily.
Insane chunni + occult freak in supplementary lessons every day: please give us at least a bonus chapter of that.