With his weight resting on his elbows on the table, Sherlock is still looking at the other half dubiously, like he doesn't quite believe he has anything worth wasting time on their association, and half-fascinated. The concept of alternate universes probably will never interest him overmuch, but the thought of engaging with a mind almost guaranteed to be at least somewhat like his own, without the baggage that comes with Mycroft, or the villainous madness Moriarty brings, or the confusing discomfort of the woman -- that is enough to hold his attention. Perhaps two of them could make more headway than himself alone. Even if not, at least it might be entertaining.

"You'll be interested to learn you're already wrong, drugs have been involved once or twice, but you're right in that I have nothing pressing to attend." He leans back coolly, a gesture calculated to demand convincing, because of course there's more to share, including his underground kidnapping adventure, but already he offers up: "You'll be wanting what I know if we're to accomplish anything."