Fair point!
He takes a breath. "Skaro," he says quietly, with only a faint tremor in his voice to betray just how scared he is. There really is something dreadfully eerie about the empty silence of this place.
"Or possibly a Dalek ship. Definitely Dalek, though."
He's never been to Skaro, but he's learned enough about it over the years, from the Doctor, from UNIT, from the Torchwood archives, to recognise that distinctive architecture when he sees it.