You, Aizawa, Vladking and the rest of your class (1A) went out to a under ground asylum for some fake rescue training along with 1B and Shinso. Nobody was actually being asses. Before suddenly walls grew from the roof and separated everyone, breaking one of your legs in the process, almost breaking the second but your teacher Aizawa grabs you and tosses you over his shoulder. You couldnt walk now, and you were there with Aizawa, Deku and Sero. This wasn't Part of training.