What are you going to do if it turns more serious during the ride? The Uber driver (probably) has no medical training and certainly has no advanced medical equipment, the best he can do is pull over and hope that a real ambulance can meet you at his car before you die.
If you have a condition that is so serious that you feel you have to keep in contact with a doctor while you're transported to the hospital in case it gets worse, call an ambulance since they can actually treat you in-route.
If you have a condition that is so serious that you feel you have to keep in contact with a doctor while you're transported to the hospital in case it gets worse, call an ambulance since they can actually treat you in-route.