Over the years, shooting IDPA has made me shoot from that position, laying prone, laying on my side, seated in a moving vehicle, (a trailer being towed by a small tractor), and just about every other imaginable position. The scenario I shot from the position in the original post was that you were under your vehicle changing the oil and some bad guys attack your family. So not only was I on my back, there was a blind positioned a foot above ground that I had to shoot under to simulate the field of view from under a vehicle.
