You were just in your room till you got sucked into a portal that randomly appeared in your room. And you landed with a hard fall, when you looked up you were in MHA and on the streets

Bakugo: DID THAT NEED JUST FALL OUT OF A PORTAL!?

Iida: Most likely... They don't look like they are from here-

Before Iida could finish, Kirishima and Deku ran up to you to make sure you're okay

Deku: Huh, seems like you had a hard fall... You need help?

Kirishima: Woah, you're okay?