Re-visit the scene in this epsiode were Locke and Ben argue over the invisible man (Jacob) in the chair. I have a theory that this was a glimpse of the future, the sequance of events however is revereserd or out of synch, Jacob asking for help, fire, the window smashing, the whole cabin rocking (Possibly the others angry at the truth that is revealed to them, or the 316's),and than when Ben is holding onto the chair pleading with Jacob, their is a gun shot heard, as Ben retreats to the wall, at this point maybe Locke had indeed shot Jacob (Or possibley Ben). Maybe Jacobs whole cabin is a paradox, as in it doesn't exsist in any one time but many, and like the island it moves, and that is why its difficult to pin down. If Ben had also had this very glimpse, it would further explain his intentions of shooting John Locke immedatly after, in fear of the future he had seen, making his motives suddenly good, as opposed ! to what we think now. I think this glimpse of the future is happening right now, and will unfold in the season five finale