Maybe the better question is "How many rounds did he waste firing the 'barrage' instead of using the front sight in the first place?"......
Jeff Cooper opined that in the time it takes to empty a 'crunch-ticker' (that's a DA/SA simi-auto) one could have just aimed and fired a few precise shots.
The thing is, once you let fear creep in it's easy to just panic some and start putting out as much firepower as you can.
The trick is to control your fear. And that is why Japanese Samurai considered themselves already dead. It allied their fears, reduced panic, and kept them steady in the face of danger.