Severus Snape- "50 POINTS FROM GRYFFINDOR!" at the HP7- Part 2 Premiere

We were at the Harry Potter and the Deathly Hallows- Part 2 premiere and my friend, who had dressed up as Severus Snape, went up to a person dressed as Harry Potter, who was gloating after dueling someone as Lucius Malfoy, and shouted this! It was amazing!