Snape didn't fail to notice the scrutiny—tit for tat, he supposed, although he was getting the impression that she was attempting to look more deeply into him than he had with her. Good luck with that he thought, presenting a nigh on impenetrable countenance.

"No, I'm a... recent arrival. Although no-one, it would appear, has been here longer than a few months, save the two crew members that never have been seen." And possibly don't even exist.