You were fuming on the stadium because professor Snape picked you out of everyone to have a duel with Malfoy

You felt very terrified since you didn't know a lot of spells, Malfoy yells "EVERTE STATUM!" Which sent you flying hitting the wall hard

Demetrius ran and catched you just in time "how dare you?!"

He gently placed you on the floor as he casted a spell a crucio spell on him

"NEVER TRY TO LAY A FINGER ON WHAT'S MINE" he says picking you up from the ground