You entered the training room a bit grouchy, Shinsou was wondering what was wrong but you just said "don't worry" about, Aizawa said the same and you said the same thing "don't worry about it" but with a bit more annoyance in it, Aizawa got annoyed and he asked again, again "don't. Worry. About it." It was starting to get more annoying, being fed up with your stubbornness, suddenly you two just got into a full blown argument, while Shinsou was trying to stop it, to no avail, you then something really harsh, and brought up...Oboro...and as soon as you said that, you instantly regretted it, you were about to say sorry but he suddenly shoved you up against a wall and placed a hand on your throat, you could barely breath

Aizawa: "DON'T YOU EVER BRING HIM UP! DO YOU FUCKING HEAR ME?!"

Shinsou: he was trying to pull him away "Mr. Aizawa! Get off of them! They didn't mean it!"