The door would have opened, seemingly of its own accord, except that Lord Voldemortist found it wide open already with ruckus music playing from inside. Could she still be here? Ah... no... not her, though she might still be around. Who else would allow students to dance on their desk and act like a couple of fools? The invisible Lord Voldemortist slipped into the History of magic office, grateful for the noise so that he could snoop around.