Hmm, can you tell me where in the video that it's pretty clear anyone from the van was picking up weapons?

I can understand some fog-of-war "I thought the camera was a gun." excuses, but just because they say on the radio that they were "possibly" picking up weapon doesn't mean that they actually saw them do any such thing.

I've watched it twice and it looks to me exactly like they shot up a van that was trying to help a wounded man.