Sometimes when the cop gets destroyed and lost the wheels, the sirens are still there instead of the explosion sound, i have discovered it a lot of time ago but now i am testing it.
Theory:
I don't know how this happens, probably, because it's too weird, also it can steer with the explosion sound.
I can make a lot of fake technical theories about it, but i know that nothing is true.
I can test it better if i put regeneration to the cop.
Video coming soon!