Plot hole: When Henderson tries to kill Jack, he learns his gun is empty. While Jack obviously doesn't trust Henderson with a loaded weapon, Henderson is an experienced field agent and he would know to check both the clip and the chamber when Jack gave him the gun. This isn't a simple character mistake, because it is explicitly said that the pair don't trust each other; thus, it is out of character for Henderson to simply accept that Jack has handed him a loaded weapon; Henderson would want to make sure.