Something the heroes didn't know about.... The LoV making a nomu as a bioweapon. It had a disease ability and LoV gave it a quirk that allowed it to spread that disease...

Bakugo was the first one... Now barricaded in his dorm room after killing and eating Mineta, stage 6 of the infection and the worst stage..

Now no one was allowed to enter or leave UA High's dorm building. Even the pro-heroes working there.

Deku was at the door of Bakugo's dorm trying to talk to him and see if he was 'better'. He was exposed but not expected to be infected.

You were with Hizashi and Shota in the common area with some of the students.

Hizashi: "How did this happen....?"

Shota: "Ask us something we know, Yamada."