Blind Witnesses
If you've ever taken courses in self-defense and the proper use of firearms, you should have encountered the concept of "creating witnesses". This means that before you fill some scumbag up with 40 caliber felon repellent, you say things loudly and clearly like "Drop your weapon; I don't want to shoot you!" and "Don't make me shoot you!" and "Don't come any closer!" This is a really good idea since there are always three fights involved in any altercation in which you use deadly force: you against you, you against the assailant and then the longest and hardest one, you against the legal system. And if you happen to stop or drop the bastard, he will be the "victim" in the wrongful death civil trial, not you. So shouting these things out will be heard by bystanders and can be used, hopefully, in the courtroom in front of the Oprah-indoctrinated jury to help counter the witness of the mommy sobbing, "He never wanted to hurt anyone!"
But forget self-defense for a moment. Suppose instead you want to shoot a bunch of people and want a chance to get away with it via an insanity plea in case you survive. What should you shout out to create witnesses for that scenario? Well, shouting "Allahu Akbar!" seems to be a good way to make people think maybe you've "cracked under stress". You also might want to give people business cards with the title "Soldier of Allah" and frequent Radical Islamist web sites. And actually having ties to an Imam with extremist views would be kind of a cherry on top for the ol' insanity plea.
Now, I know what you're thinking. Won't people maybe think that you are actually an Islamist terrorist who had planned the incident with cold, calculated premeditation if you did and said all these things? Surprisingly not; it's more likely you will be diagnosed with Pre-traumatic Stress Disorder. Go figure.