"You phase inbetween realities or time/space," the Doctor interpretted. "Which means you could walk through things or people because they aren't really there. The TARDIS doesn't work like that at all. The inside is in a different dimension than the outside but when you go in, you're definitely there."
He took the screwdriver from Kurt's tail without batting an eyelid. "Prehensile -- very helpful," was his almost throw-away comment. "I wonder how far away we have to be for it to work." He glanced at the watch for a moment. "You can show me one day when we're away from here." The Doctor looked at the side of his sonic device, reading the results of his scan before laying it on top of his frock coat.