Thanks for the link! I assume you're speaking about the part between 1:30 and 1:40. a person wearing black appeared behind the lines of Palestinian forces. This would be pretty alarming to the fighters, as the person in black could be undercover or off duty soldier. The person was probably yelled at and told to get down, but proceeded to move in the wrong direction (could be language barrier). It seems that this is when someone opened fire, but you can see smoke appears on the ground noticeably far from the person. This means whoever was shooting shot at the ground, to alert the person in black. It was immediately after that that the person in black dropped to the ground.

Most likely, they dropped not because they got shot and killed, but because they complied after being warned with the gunshots. If you're shooting to kill, you wouldn't be shooting on the ground far from the person, or even their legs. Moreover, if you look close and zoom in, the person is seen moving after they drop right before the clip ends, indicating they're probably still alive, and the video clip ends immediately after.