Continuity mistake: After the plane is docked Stallone and Statham enter the customs agency. Statham is wearing a camera on his neck with a small lens, he even shows it to the customs agent. After leaving the customs they walk across a square. The camera now has a big zoom lens attached to it. Statham is not wearing a lens bag. Where did he get that lens from? Also strange is that the lens is set in manual focus instead of automatic. Yet the picture stays focused even zooming in. This is not possible without looking at the screen. Plus the camera is turned off in the close up shot, with the image on the LCD composited in. (00:28:15 - 00:30:45)
Continuity mistake: Paine punches Sandra and bruising appears immediately. However, when we see Sandra shortly after, she has no bruising at all. (00:56:20 - 00:57:05)
Continuity mistake: In the scene When Gunner is leaving Barney's garage and says "Be Careful", he raises his right hand pointing back towards Barney but when the scene cuts to a shot looking into the garage from the outside, his left hand is raised and pointing back.
Continuity mistake: Barney's tattoo swaps from being a drawn tiger to a drawn woman. (00:14:35 - 00:42:05)
Continuity mistake: At the very end, after saying goodbye to the girl, when Stallone enters the cockpit he has a bulletproof vest on, when cameras change he doesn't have it and in the next angle he does have it on again. (01:32:00)
Continuity mistake: In the first flight scene, looking out from the cockpit, some ordnance is visible on the wings. Later, viewing the plane from the outside, there is no ordnance, only fuel tanks.
Continuity mistake: When we see Barney and the army both racing through the streets, there is a little boy who throws something at the army. In one shot he starts the throw with his left arm but finished it with his right arm. (00:39:20)
Continuity mistake: When Sandra is captured and tied up, she is tortured with water. All the way through this scene her hands that are tied, change from being right over left hand, left over right hand etc.
Continuity mistake: We see the Expendables flying to the island for the second time and then the shot changes to show some military jeeps entering the palace grounds. In the overhead shot of the trucks arriving, the tyre marks are wide and indistinguishable from many over tracks. When the shot changes to in front of the palace, the tracks are very clear and defined. (01:05:55)
Continuity mistake: During Gunner and Yang's fight, Gunner puts his foot through a wooden pallet. The shot changes to Yang running at him, and now he is stood around 4ft away from the pallet ready to pick Yang up. (01:01:50)
Continuity mistake: During the car chase, Yang shoots out part of the rear window of an orange 4x4. This hole then keeps changing place between the following shots. (01:00:00)
Continuity mistake: Just as Barney realises it's Gunner who's attacking them, he knocks part of his chrome bumper off the truck and it's dragging along the floor. A few seconds later the bumper is reattached and fine. (00:59:40)
Continuity mistake: When the orange 4x4 is hit by the bin lorry, the drivers side window is smashed. However as the truck pushes the 4x4 just 2 seconds later the window is now intact. (01:00:15)
Continuity mistake: When the contact pulls over and lets Christmas out of the truck, the truck is parked next to some green vegetation. When the truck pulls away it's in a completely different spot. (00:34:40)
Continuity mistake: When Christmas hands his passport over on the island for the first time, the way the customs officer grabs it differs between the CCTV footage and the actual camera angle. (00:27:00)
Continuity mistake: When Christmas is walking across the street just before he see's the army, he is holding on to his camera. Angle change and his hand is no longer on the camera. (00:20:00)
Continuity mistake: When we see Barney pull into Tool's garage, his truck is 3/4 into the garage. When the shot changes, it's only just entering the garage. Note the shadow on the bonnet of the truck. (00:22:30)
Continuity mistake: When the pirate is following the laser sights on his hands, the dots are changing positions massively between shots. (00:04:50)
Continuity mistake: When Barney pulls up at the lights in the pick up the following car is right behind him, cut to a front shot and the car behind is a fair way behind and we see it pull up behind a second time.
Continuity mistake: When Christmas sets up the guns on the front of the plane he turns to Barney raising his right hand. As he turns back in the close up he starts to lower his left hand, this is a continuous scene.
Answer: The back stories of the individual members of the team have never been elaborated upon. It is never stated where the members received training.
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