I don't think doctors have the right to break the law just because they are going to an emergency. Obviously, the ideal situation is to have a police escort. But doctors are human like the rest of us, and I think it would be bad practice to allow them to speed even if the situation seems dire. If they hit someone, particularly a child, then there will be two deaths rather than the one that might or might not occur because of the doctor's delay in arriving. Anyway, given modern medicine, it seems unlikely that the arrival of a doctor is so critical that the patient cannot be stabilized for a sufficient amount of time to allow the doctor to get there at a reasonable speed.
Of course, if it was someone that was special to me, I would be screaming for the immediate presence of the necessary doctor!!!