When the police are responding to an emergency call we need to get there ASAP, so pull over at the nearest place that it is safe to do so.  We understand that there may not be anywhere to pull over right away so that we can pass you.  So just put your turn signal or hazard lights on so that we know you see us and watch for that safe place to pull over to the side of the road.  Traffic coming toward a police car is also required to pull over to the side until it is passed.