Continuity mistake: Towards the end of the episode, when Locke is preparing to shoot Ben, Ben starts talking about Charlotte and her team. Locke is then holding his gun in his right hand, and holding Ben with his left. As Ben is saying "Because I know what they're doing here", there is an angle change, and Locke is suddenly holding his gun with both hands.
Character mistake: When Jack and co find Frank, we see Jack checking for a pulse and declaring there is one. However, Jack is using his thumb to check for a pulse on Frank's wrist. As a doctor, Jack would know your thumb has its own pulse. (00:33:40)
Continuity mistake: In Tunisia, we see someone grab a newspaper and hold it by the side and top in a long shot, but from opposite sides in the close-up shot. (00:22:10)
Answer: He was eating a peice of an orange with the skin still on.
XIII