On March 18, 2003, Apple had only released the 2nd Gen iPod, with the 3rd Gen due out in April. The iPod prominently featured before the first mission appears to be the 6th Gen, which didn't debut until Sep. 2007.
Simply shooting someone in the head would not guarantee that their thumb would stay on a dead man's switch. When you die from severe trauma to the brain usually all the muscles in your body contract, but not always. Shooting the kid in the head could of very well caused his suicide vest to go off. Even if his muscles stayed contracted, the triggering device could of been knocked loose from his hand when it hit the ground.
(at around 2 mins) Although set in 2003, The iPod visible just after the line, "Good hunting, boys. I'll see you back for breakfast," is a fifth generation iPod and was first released in 2005.
Just after the shooting of the reporter's crew on the bridge, as the camera zooms out, you can just see a couple of crew members crouching in front of the van the reporter was placed in. You can also see their profiles in the shadows.
Captain Collinson is seen wearing parachutists' insignia on a maroon background. That particular badge was worn only by Junior Leaders [Boys' Service] on PT vests, and did not constitute a qualification badge.