You think it looks like a camera now. Keep in mind that the helicopter was called in to look for a group of men that were firing at troops on the ground that are down the street from where the "camera" is pointing at 4:15. Again, an RPG isn't quite heavy. The standard RPG-7 weighs 15 pounds.
To me the chopper crew is just sloppy and they shouldn't be. I get why some grunt storming buildings may accidentally shoot someone holding up a broom or something. But these guys should have the discipline and training to be able to stay cool and wait things out. There's clearly not a full blown street fight going on at this location. And what happens at 5:13?
But frankly I'll always be on the side of war corespondents after reading "My war gone by, I miss it so" and seeing "War Photographer".
I would be very very surprised if the device at 4:12 is an RPG. It looks and behaves like a long lens camera. At 4:15 you can see a space between the device and the body of the person. An RPG is also quite heavy and has a distinct shape and you wouldn't generally turn it around a corner.
As there also according to wikileaks were photographers on the scene. It's just far more likely that it's one of the front two guys who carries something that picks up his camera and take some pictures. If that is the case, then I would have to question the chopper crews ability to recognize weapons on the ground.