Toru was hit by a strange quirk on her way to class by accident, one that disabled her quirk for a certain amount of time.

Though she had only realized it as Iida stopped her by the door. At first, she checked her uniform, making sure she was wearing her tie correctly. Which she was, so that only served to confuse her even more.

Iida: "Halt! I don't think you're from this class." He said, not recognizing her now that she was visible.

Toru: "Eh!? What are you talking about, Iida??" She pouted, a frown forming on her lips

Listening in on the conversation from your seat, you picked up on the clues and put together that the 'strange girl', was in fact, Toru Hagakure.

It was kind of shocking, if you were being honest. You've never actually...seen her, especially since her quirk doesn't really have an 'off' button.