I really love the fact that the teacher name is GREY but her personality is like pure cliché black without any interesting thing lol.
I mean seriously if grey and the MC did have some mutual understanding / trust in each other but their goal where incompatible it could have been interesting but it s just another stupid vilain without any personality apart from being the big bad evil guy who is very evil and bad
so? run ray and you not running? i know you got the pressure from the sensei but won't that lift out because mc do smth and you can breath freely and run? so the mc can more focus? well manga logic work ...