"It's only the fact that I witnessed her entrance that's allowing me to entertain any piece of this." Ducky sets the knife down, takes a deep breath, and...shoves a lot of what she's allowed to show so far back under the polite maid persona. "Tea or coffee, miss?"

For the moment, listening and thinking will serve her better. She's still an unknown quantity to some degree to the stranger. Whatever she knows, it can't be the whole of the matter.