And we're supposed to take everything that comes out of this guy's mouth as fact?! He's been lying continuously since he's been in the hatch - even after being called out for his original story, he tries to lie again only to be trumped by Sayid's dollar bill with the note on it. Why should we believe the new stuff - just cuz he said "i'm done lying?" But i'm not convinced that he's there accidentally. I think he's there to get info. I mean if the "others" wanted to come get him, don't you think they have the power to do so?
Anyway I think this episode served a greater purpose. What's the worst thing we all fear? That at the end of the series this whole thing will be somebody's dream or hallucination. Well, by bringing in this episode now, i think the writers are trying to rassure us that they wouldn't do that to us.
It's really amazing how unique this show is. Each week there are some answers but usually more questions/mysteries are created. And of course each week you get more drawn in.