I can see the legal part of negligence of a hp. If you are calling an ambulance you are putting them in a position where they owe you a duty of care. And legally and ethically, as a health carer, it is our responsibility to meet that duty of care to the best of our ability. Just as nurses are expected to continue resuscitation measures on a pt until a dr has declared them deceased, unless unsafe to do so. And in a way that duty of care does make them fully responsible for your care, until someone more experienced/trained takes over.

By saying this I'm not saying a hp has the right to force care, but it is their obligation to try to enforce the best care possible.