Even if there is a paired shoulder, drivers are required by law to pull over and make a complete stop. That could mean driving into the brush a bit. Instead, the ambulance driver would pull off and still be halfway in the road, then having the driver continue until the driveway appears.
Upon the urgent approach of an authorized emergency vehicle lit up and making noise, under normal atmospheric conditions, the surrounding traffic must pull over. The motorist of every other vehicle on the road must give the right of way to the ambulance and remain stopped until the emergency vehicle has passed.
If this is not accomplished, there could be multiple collisions, which could even cause more emergencies, and it will hold up the person in the ambulance who needs immediate attention.