Notes, Notings, and Common Refrains

I've seen snippets and brief quotes from this scene, but until I just watched it, just now, I never caught on that the Doctor actually says they're aliens: "Susan and I are cut off from our own planet, without friends or protection."

Now, granted-- that could have meant he and Susan were human colonists of a distant planet from the far future, but it sure seems to me like the show's creators were leaving the door open to him being an alien species from the get-go.

Neat.