It took Twilight a moment to work out what Trixie was talking about. As soon as she did she fired the spell she used to free her friends from the influence of Faust's magic right at him. He howled in pain and fell to the floor clutching his head, but Twilight had no way to really tell right at that moment if what she'd done had actually worked. Instead she used the short moment of confusion to knock the guards back, and slam open the nearest window.