No, no, no, you don't take the stator guard or the grill off the siren for display! Are we looking to harvest fingers? If you do want to show the rotor, for a "how sirens work" display or something, you put the whole siren in a display case with a motor to turn it about 15 rpm or so. And how much louder would the siren get? Not so anybody would ever notice. You've been bitten already, Robert, think what could have happened to you.
P.S. That would be a good display -- the siren in a case, spinning at about 15 rpm to show how it works, and every half-minute or so (or when a button is pushed) it speeds up just enough to make a sound. Good demonstration. It'd need a little programming of a controller, but nothing outrageous. Adam Smith could have it going in no time.