Career criminals, like the cops usually would be dealing with, “kow the drill.” They’ve been in trouble with the law enough they know what to do if so confronted as if second nature. But law abiding citizens don’t automatically know what posture to assume. And it would fly all over me, if I am breaking no law and a cop not only wants to arrest me, but he wants me “Down on the ground—now!!”
I agree. My first reaction would be "What the...?" Then I'd try to explain or show that I wasn't a threat. And I'd probably get blown away like the victim in this case was. None of the witnesses have given any indication that he was beligerent or argumentative or threatening in any way. This appears to be a very bad and ultimately tragic performance by the police. I don't think that Gill Grissom and his team from CSI will be able to pull this one out of the fire.