I was checking a FaceBook Lost fan site, and in an article that was complaining about the Paulo and Nkki's episodes and death, a guy from London called Michael Broad said this:
I still think it served a purpose, re the Medusa spider's venom. Wasn't Sayid knocked out by the darts for like 48 hours? I think the men worked for Ben and the poison was in the dart. Also, could be the same with Locke, and, a wild guess but maybe Christian. Anyone remeber how he 'died'?
Christian is still walking around the island, and maybe that's the way that Locke has to come back to the island... looking dead doesn't mean you are...
Any ideas on this?