"Look around," the Doctor offers. "Look at this world. This is Gallifrey. Of all the planets in the universe, not many can be said to be more dead and gone than Gallifrey is. Everything on this world, everything that belongs on it, you've long ago harvested and dragged off. Either I belong here, and there's no point in collecting me another time... or I don't, and you might be making a mistake you can't afford to make when you swing that scythe."