You are serving as medical command at one of the largest Motorcross tournaments in your state and are called to the scene of a "biker down." On arrival, you see a 16 year old male lying on the track. He is alert and oriented to time and place and tells you that he only fell off of his bike, and based on his location and time that he had not gone through any jumps (again, no great fall). However, you note that he is not moving his left arm, which is rotated at the elbow. You ask both him and his father if he is to be transported via ambulance. Both say yes.
Your state is a "you call. we haul" state, so if they call 911 for anything from a tick bite to a cardiac arrest, if they say that they want an ambulance to take them, you take them.
Your partner proceeds to splint the elbow while you contact dispatch, request the second unit to respond, and establish communication with that unit while it is en route. The second unit arrives within six minutes of your call. They load the patient onto the cot, but just before they put him in the ambulance, he changes his mind and decides to go to the hospital by car. Your partner verifies that they DO NOT want the ambulance and informs the patient that they can do some things en route (ie, IV establishment). You notify dispatch so that they can notify the hospital that he is coming by car. At that point, your supervisor gets on the radio and asks if you rendered any treatment. You state that you splinted him. Your supervisor says that you can't do that and orders you to call him immediately.
Was there anything that your crew missed? What reasons would the supervisor have for his reaction?