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)
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: 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.
Continuity mistake: 4-3: When Sayid has shot the man on the golf course, he lowers his arm twice. (00:05:40)
Continuity mistake: When Sayid sits down in the café, the woman he sits opposite is playing with her hair in the shot facing Sayid, but has her arm down in the shot facing herself. (00:06:33)
Continuity mistake: When Sayid finds all the passports, he opens one and the way he holds it differs between camera angles. (00:25:00)
Revealing mistake: 4-3: When Sayid closes the woman's eyes in the hotel room, it is clear he doesn't touch her.
Continuity mistake: 4-3: When Sayid is in bed with the woman, his position changes depending on the angle.
Revealing mistake: Episode 4-4 "Eggtown": When Locke is in the basement hallway, he slams Ben's breakfast tray against the wall. The wall moves like it's thin plywood. Odd since basements are either thick wood or concrete over packed earth. (00:02:30)
Continuity mistake: When Kate and Sawyer start arguing, Sawyer's hair changes back and forth between shots from being parted to combed back.
Continuity mistake: Just after the title sequence, we see Faraday holding a map in two hands in a close-up, but with one hand and one hand pointing at the map in a longer shot. (00:10:40)
Continuity mistake: When Kate is aiming the gun at Juliet and The Other Woman, the person she is aiming at changes depending on the angle.
Factual error: When Michael and Tom end their phone conversation, we hear a dial tone. But cell phones do not emit a dial tone when a call is disconnected.
Visible crew/equipment: S4xE8 "Meet Kevin Johnson": Near the end, Karl has nothing in his left ear when he and Alex sit down and start talking, but when Karl falls onto the ground, the actor has a wireless earwig device in his left ear in his close-up, before Alex turns him over. Then, when Alex sits by the tree distraught, Danielle tries to convince her to listen, and in Alex's extreme close-ups, she has a mini lav mic (similar style to DK3 series) at her right ear that becomes visible.
Continuity mistake: S4xE8 "Meet Kevin Johnson": Near the end, Danielle, Alex, and Karl stop for a couple of minutes to drink water, and when the bullet hits Karl's water bottle, in the close-up we see the low level of water inside the water bottle directly above the leak, but in the next shot there's much more water inside the bottle above the leak.
Something Nice Back Home - S4-E10
Continuity mistake: At the start, Jack pops a bottle of pills, and the orange bottle is in his right hand. The camera cuts, and now the orange bottle is in his left hand. (00:01:30)
Cabin Fever - S4-E11
Continuity mistake: In the scene just after John Locke's teenage mother runs from the hospital room, the nurse converses with the grandmother. You can see her put a cigarette to her mouth with visible lipstick stains on the wrong end of the cigarette, possibly from previous takes. (00:32:10)
Continuity mistake: "The Variable": When Faraday is on about the variables, he has his jotter in his hands. Camera does a quick cut and it's now on the floor.
Answer: Using a mold, a realistic pregnancy belly is made of latex (rubber), including the distinct belly button, to suit the proportions of Emilie de Ravin who plays Claire. It is then painted with a special paint/adhesive compound that adheres to the surface and for shots of the actual belly, additional veining and stretch marks are airbrushed on.
Super Grover ★