Continuity mistake: When Bryan goes into the store to buy the karaoke machine, there is a clock visible on the wall behind the merchant. During this scene, the minute hand jumps ahead by 5 minutes between the first shot of the merchant and the second shot 6 seconds later. (00:01:55)
Continuity mistake: When Kim runs to hug Bryan at her birthday party, her braid in the first shot showing her face is behind her back. In the next shot from behind her, her braid is over her right shoulder. In all subsequent shots, it remains over her shoulder. (00:03:40)
Continuity mistake: When Peter takes the picture of the two girls, Kim's left arm is down, but when Bryan is viewing the pictures from the phone, the picture shows Kim holding Amanda's elbow. (00:20:45 - 00:36:10)
Continuity mistake: When Kim is kidnapped, she describes the man "Beard. Six feet. Tattoo right hand, moon and star." When Bryan listens to the tape in the jet, she says, "Mustache. Six feet. Tattoo on right hand, moon and star. Dad!" (00:27:50)
Continuity mistake: In the scene where Bryan is interrogating Marko, he pulls out the picture of Kim in his left hand, then the scene changes to Marko's face when he spits on Bryan, the picture changes to Bryan's right hand (because that's obviously his right thumb), then the scene quickly changes back to Bryan holding the pic in his left hand. (01:04:15)
Continuity mistake: When Bryan is interrogating the man using the electrical chair, after he flips the switch the first time, Bryan is seen taking off his tie. However, after Bryan flips the switch the second time, in one of his closeups Bryan is wearing the tie, but in following shots the tie is gone again. (01:05:35)
Continuity mistake: When Bryan is handcuffed to the pipe being choked from behind, the pipe breaks, and he headbutts the guy behind him. When he goes in for the headbutt, his left hand comes down as if he is no longer handcuffed but then in the next shot, he's suddenly handcuffed again. (01:14:42)
Continuity mistake: When Kim is up for sale, before Liam can see her face, her hair is combed, then over her face, then combed again. (01:21:40 - 01:22:45)
Continuity mistake: In the scene Brian and the guy that bought his daughter are fighting on the yacht. After he jumps through the glass and the guy starts fighting with his knife, he is swinging to try to hit Brian but hits a lamp shade. You can see in the scene after that the lamp shade is gone, but when the camera goes behind Brian you can see that it is back on. (01:23:50)
Continuity mistake: In the scene when he is driving his daughter to the airport before she flies to France, it appears they are riding inside a late model BMW 5-Series. This is apparent by the tan leather interior and the double adjustable padded headrests and rear seat headrests. However, when they appear at the airport terminal, he is seen unloading the luggage from his personal car, a 2005 Nissan Sentra GXE with a basic gray cloth economy interior (Confirmed by the Features on the DVD release)
Continuity mistake: When Bryan chases the spotter, all of the cars that had to stop are all positioned at different angles. After the spotter dies and Bryan walks back along the bridge, one of the shots shows all of the cars now parked in a perfectly straight line.
Continuity mistake: When the spotter is organising with the girls to go to the party outside their apartment, behind him you can see a grey Peugeot 806 people carrier with nothing behind it. In the shot as he walks away, a dark coloured car has now appeared behind the Peugeot - not enough time had passed for that to happen.
Continuity mistake: When the spotter starts singing "California Girls" to Kim and Amanda, Kim puts her hand to her mouth, in the next shot from behind, her hand has gone from her mouth.
Continuity mistake: When Bryan rescues one girl from the construction site brothel, he steals a white Jeep Cherokee to escape. When his pursuers start shooting during the chase, a shot of the Jeep's rear shows both red tail light lenses are gone. But the very next shot showing the right side of the Jeep proves they are intact.
Continuity mistake: When Bryan meets his daughter in the restaurant and gets her a milkshake with three cherries, as the scene cuts from Bryan to his daughter and back, the whipped cream goes from being on top of the milkshake to melted and then back again to being on top.
Continuity mistake: When Bryan shoots and kills the auction leader in the elevator, his right hand is on the ground. In the next scene where the elevator opens, his right hand is on his stomach even though he's dead.
Continuity mistake: When the pop star and Liam are getting into the car to leave the concert, her hair is dry and perfect, but in the next shot when they are in the car, her hair is drenched.
Continuity mistake: When Kim is in the café talking about the trip, the hair on the right side of her head covers and then uncovers her ears multiple times between shots.
Continuity mistake: Just after Kim was taken from under the bed, Brian talks to the Albanian on Kim's cell phone. Just after the bad guy tells Brian, "Good luck," the loud clicking sound of a heavy, old-style phone receiver being hung up is then heard, disconnecting them. However, a cell phone does not make that sound when a call is ended.
Continuity mistake: When Brian meets Kim at the café, her sundae keeps changing from being untouched to touched.
Answer: Actually, what Bryan Mills did was perfectly possible. He strapped a mobile phone to the two way radio, and used the other two way radio to talk. By speaking into his radio, it transmitted it to the other radio, where the mobile speaker could hear and transmit his voice. The French police would have been able to triangulate the source of the mobile phone signal from the particular 'cell' (i.e. area) that the mobile was using - while that would lead them to the phone position, he'd be elsewhere talking on the other half of the radio.
GalahadFairlight
Two-way radios have a push-to-talk button. There's no way he could operate the button remotely.