I think I have identified a problem with Fire Engine sirens that continuously play throughout the game in Freeplay(or possibly missions, haven't tried). Whenever you send a Fire Engine to a fire and click Rapid Deployment without turning the siren off, the siren button becomes unclickable with the circle and slash image on top of it. The siren will now stay in that spot for the rest of the game(meaning that even if the fire engine leaves the area, the siren will still be playing where the engine previously was). Once all hoses are disconnected from the Engine, the siren button becomes clickable and still looks as if it is on. When you click the siren button to turn it off, the siren still plays and when you click the button again, it creates a second siren on top of the other(however, this one can be turned on and off like normal.) So the game basically creates two instances of the siren, one stays at that spot, and the other acts like the normal siren. Does that make sense?