http://www.reddit.com/r/WTF/comments/bmooi/wikileaks_video_j...
It seems plausible to me that these guys are seeing this situation all the time: they fire on a group of people, some are left wounded, and vans show up to collect weapons, but also grab wounded/bodies to try and look legit from the sky. Being used to tactics like these, I can understand how anxious they were to get clearance to fire on the van; who knows if they are going to fire on the helicopter or speed off. It wasn't clearly marked as a medical vehicle, and it sounds like everyone over there knows that you will be fired on if you do something like this.