[ there's a pause before the Doctor answers with, ]

Let's go with the mummy on the Orient Express—space Orient Express, mind you. And it's a bit of a space mummy. I was bothered for a while to check out the Orient Express, due to the mummy rumors. Turns out that everybody on the train was brought there in order to study the mummy: figure out what it is before the space mummy kills everybody. Turns out the mummy wasn't really a mummy, but a soldier kept alive through malfunctioning future tech. A statement of surrender was enough to relieve him of his duty.

So there we go. Meddling turned into letting a poor soul have his well-deserved rest.