9 American's killed in Afghanistan...

I'm confused. My source is ABC Evening News. How do 9 American soldiers (okay, 8 soldiers and a contractor) get killed "exectution style"? I've always been under the impression that exectution style involves having the victim kneel and then shoot them at close range in the back/bottom of the head. I can hardly imagine 14 armed soldiers consenting to this. Maybe I have my definition of execution style incorrect, or else someone's facts are wrong. If the man had them line up, how was there no time for someone to get a shot of their own off? And how weird is it that though all the American's died, the Afghani's there were only wounded (and to what degree)? It's just odd.