I think the thing that scares me the most about this episode is that it proposes a world in which there is more than one of me [http://img683.imageshack.us/img683/5703/feeddump.png].
That alone is mind-numbingly insane enough to destroy societies, civilizations, and the entire omniverse. More to the point, it means I'd have to meet myself. I wonder how I'd react to that.
Otherwise, I'm genuinely more pleased with this show by each passing episode. Color me impressed. And pluralized.