Serious answer: I don’t know what the law is in the US.
In the UK where I trained and practiced, there is no situation of overruling in the street — or at least I never saw one. Our police force is incredibly well trained in these regards, and in any emergency, paramedics are usually first on the scene.
Police will often accompany people to hospital, and wait patiently until the healthcare professionals are finished with their work before dishing out justice.
In hospital, the physicians/nurses/others have the final word. I have demanded the removal of police officers from the resuscitation room on a few (guess 5) occasions. Sick people get agitated, and that makes them sicker.