Oberon has done an excellent job above with his timeline.
I will also say this - to those of you who have never seen combat - never been shot at, and never had to pull a trigger - you have no understanding of the stresses involved.
The comment of 5:53 - encouraging a person to reach for a weapon - is actually a comment that makes note of the ROE - if he DOES reach for a weapon, he confirms his own status as a combatant. Now - you just pulled a trigger - you now have an injured person in your sights - do you want to see him reach for a weapon - proving he is a "bad guy" - or do you want to see him hobble off, passing by a weapon and instead reaching for safety. If there is any doubt in your mind about him actually being a combatant - you know you have already injured him - if he is not a combatant - you have to face the fact that your actions marred for life an innocent person. It is part of the mental rationalization to want that person to reach for a weapon - which absolves you of the wounding and gives you the (somewhat shaky) ethical ground to put him out of his misery.
Now - a comment about what is conspicuously absent in this discussion. You have a "reporter" - often local populace member - in an area of conflict - and around people with weapons. In addition, you have a unit of your own army nearby. The video shows the photographer was going to take a picture of SOMETHING - and being a "war correspondant" - you can bet a doughnut that he wasn't going to take a picture of a little girl playing with her doggy in the park. Something was going down - and the "reporter" knew it. Otherwise he wouldn't have been setting up to capture it. The fact there were armed elements in his immediate vicinity show that there was action about to occur (or in the case of the "sneaking" aroung the corner - already going on). Against whom - is unknown. It might have been the unit entering the area - it might have been another militia group, or any other possibilities. But the reality is $hit was about to get (or already was) hot, and the intervention by the soldiers involved obviously stopped things. Good or bad - we won't ever know.
But to claim that the entire thing was just "indescriminant" killing by US forces is a total croc.