Logic presents two possibilities: either Rukia is amnesiac, or there's been some kind of time-hiccup, and she's either never been, or has yet to go. "Maybe ... perhaps it's in your future?" The other possibilities are a little too disturbing. "I apologise -- I'm not really sure how I got here, and this is all very confusing, I'm afraid." The second question ... as always, tricky to answer. Especially since Hogwarts-Rukia knew the whole story. She decides, for now, to stick to the barest truth. "I'm a schoolteacher. From the Discworld, originally." A wry smile; she can't help it. "And I've had an excessively interesting life."