I know I'm on the other side of the world but I believe the rules are very similar down here. I drive a fire truck, and as long as the lights and siren are in operation I'm permitted to go 20 kmh over the speed limit if I consider it safe to do so. However, If I'm involved in an accident and It is found that my actions were the cause of that accident, I, as the driver would be prosecuted for dangerous driving.