I'd say '
There's Something Not Quite Right About Him'. He just seems a little too comfortable with the whole conscious switch thing. I know he's gone through it with Brendan and Minkowski, but still he seems a little too relaxed around it. There's an eerie calmness about it that makes me uncomfortable. Even when Sayid went on the one man wrecking crew mission he stayed completely calm. Plus he seemed a little to happy about administering that needle
But that's probably just me.