I always thought Hicks would not just shoot him there and then. I always had the impression that Hicks would of used Burke as some sort of bait for the aliens, rather then shooting him on the spot. Something similar to making a prisoner of war, walk across a mind field to test the path for landmines ect. I like to imagine, Burke would of been forced to walk Infront at gunpoint to see if any Aliens were waiting to ambush them. The did have motion trackers, so it would of been useful to track Burke why he is forced to walk in front why the rest of the team hangs back to see if any other blobs starts to appear around Burke. Ya the motion trackers could of still done that job without using Burke. but by using Burke as bait, they could of triggered any aliens waiting in ambush a little earlier and give the marines a few more vital seconds to react when escaping operations. If they all made it out alive and Burke was unharmed I see 2 outcomes for him. He is either sent back to face charges or he if left behind on Lv426.