He is fast and it's frustrating, but the TARDIS ignores his taunts, standing still in the arena as he runs past her. She refuses to be intimidated by a vampire. And besides, two can play this game.

The TARDIS lifts her arm and fires -- bang bang bang bang bang bang -- each round fired in a different direction. Sorin can run around her all he wants, but she has unlimited bullets with this projection and one of them has to hit eventually. Let him run when he's wounded.