Tomoe would teach the healthy students at school during the mornings and afternoons. But in the evening and night, he would teach the ones who were still in the hospital. This was, pretty strange to the students. It seemed,

pretty uncharacteristic of their teacher to be hardworking yet it also seemed like he wasn't bothered by it.

Moreover, he seemed guilty over the fact that he put them in danger. Supposedly, while they were asleep, Tomoe got on his hands and knees and apologised to all of the parents. News outlets claimed that it was due to

  "Someone tripping and causing everyone else to fall with them on the way to the Fushimi-Inari Shrine while on a fieldtrip to Kyoto causes entire class to be hospitalised!"

  The entire experience also scared/scarred some of the students and/or parents so quite a few asked to transfer classes. Of course, their memories were promptly erased and replaced thanks to Tetsu's resourceful knowledge. Him and very few others have this power but, you and I have seen it pretty much everywhere, haven't we? The ones who transferred were:
-Kaito B'xejn

-Junes Padrão

-Danye Strigoi

and Hans originally wanted to go, but his siblings convinced him not to.

When they asked to transfer classes, that was the first time the students ever saw Tomoe not being stupidly stubborn. All he did was apologise and not put up much of an argument. The students who stayed started wondering, "Did Tomoe change? Or does he simply put up a front?"