You were captured and locked in a fell down below the castle of Hogwarts, it was too dangerous for you to go out there. So Dumbledore kept you there, you tried to convince him that you weren't a threat, but he didn't believe you. One day, you got a mail, saying that someone you loved had been captured and is about to die if you don't come to save them immediately, rage engulfed you and you broke free from the chains. Snape saw you escape and followed you

"Fuck! How did they escape!"