"It doesn't." It only did in the genetics lab because of his wards, he thinks; it looks catastrophic but only because magic tends to look very big when it goes wrong. He suspects it would be hardly - if at all - noticeable otherwise. "It isn't like Hogwarts. You can walk down a straight hallway for hours and find yourself looping. Maddening things like that."

Truth be told, Severus is getting more usual data out of observing the problem than he was out of it behaving normally. But let's not mention that. Instead, let's go. Out. Severus walks away, obviously expecting Lupin to follow him. Down a hall, throughout the varying doors and lab windows and workspaces. "This was made to employ thousands of people," he says absently, passing a door with a ward spray-painted on it. (Don't ask.) "Discounting medical and agriculture, the overall science department has five people working in it."

... There's plenty of room.