Maybe the armed citizen should have had a .45 instead of a 9mm because everyone knows 4 shots to the chest with a .45 would...oh wait.....
In all seriousness though - anyone know if the guy killed was on anything but an adrenaline high? Anyone know what type of ammunition the shooter used? I'm surprised, if it was a close range encounter, and those were 4 good shots center mass, that the 5th shot was required. Just goes to show you - hand guns are small!