You have a very good point. And just like the Miami FBI shootout, chaos can and will happen.That's a good point, but I am not sure it covers the whole issue. I am thinking of the Skokie shootout where the the cop was a master firearms instructor who said in an interview that he practiced a lot. He hit the perp 16 times with a .45, including two in the head and the guy kept returning fire until he got a third hit in the head. BTW, the perp was found to NOT be under the influence of any drugs.
So the proposition is that you have to get a pure, absolute center of head hit with a caliber that has high penetration, on a moving perp. Anything less might not get it. If someone with that cop's training couldn't do that, what chance do most of the rest of us have no matter how much we train? There has to be another solution.
But, I suspect the case you refereed to is the exception, and not the norm, so I'll continue to practice the normal double tap and look and see if there are other threats.