Continuity mistake: When Barney meets his friend and they go for a hug, they connect. Camera cuts and then they connect again. (00:00:20)
Continuity mistake: Christmas fires the flare from the left side of the plane. In the following shot, the flare appears to be coming from the right hand side of the plane. (00:00:25)
Continuity mistake: When the pirate is following the laser sights on his hands, the dots are changing positions massively between shots. (00:04:50)
Revealing mistake: When the pirate leader holds his hand up looking at the laser sights following it, his palm is facing away from the expendables, but the red dot still appears on his palm. (00:04:50)
Continuity mistake: Barney's tattoo swaps from being a drawn tiger to a drawn woman. (00:14:35 - 00:42:05)
Continuity mistake: When Tool is finishing Barney's tattoo, he has to do the "able" of Expendable. We see him do part of the A, Christmas arrives and it's suddenly finished as shown by Barney looking in the mirror. (00:15:20)
Continuity mistake: When Tool and Christmas having the knife throwing contest, Christmas's knife lands off the board. When he collects it, it is now just on the edge of the board. (00:17:00)
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 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: 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)
Revealing mistake: When Christmas is filming the army, you can see the switch on the camera is at the "Off" position. (00:29:30)
Other mistake: When Statham has a 5d mark2 Canon camera there were a couple of mistakes in the close ups. At 29:58 the camera is actually off. At 29:55 it shows him twisting clockwise and you see the lens extend then it shows the lcd screen all zoomed in. But the lens he is using is a standard telephoto its only 24mm-70mm and he zoomed out to 24mm which is really wide. Plus that particular lens extends when it is at its widest unlike most other lenses. (00:29:55)
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 asks Sandra if they are close, he is sat facing her in the tuck. Camera changes and he is now facing the front. (00:34:50)
Continuity mistake: When Christmas and Barney get into the fight when the militia are trying to take Sandra, Christmas uses a throwing knife to kill several men, however in most of the shots, but not all, there is no blood on the knife whatsoever. (00:37:00)
Revealing mistake: When being chased by the military, there is a shot of the blue truck driving towards the camera down a street. In this shot, the tyre marks from previous takes can be seen on the ground. (00:38:00)
Continuity mistake: When Christmas says "If we get out of here it'll be a miracle", he is sat properly. Camera cuts and he is leaning forward with his arm behind his back. (00:38:15)
Continuity mistake: When Barney is driving Sandra's truck there is a shot of it sliding through an open area. Camera cuts to Sandra saying "How can you leave?" If you look out the window they are now driving down a residential street. (00:38:40)
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)
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.
BaconIsMyBFF