Could someone please explain to me why it is necessary to leave the ambulance doors open when it has been called to an emergency and the medics are in the house dealing with the patient?

After all, the doctor doesn't leave his car door open. There must be valuable equipment in the vehicle which could be stolen.

And if the patient has to be taken to hospital, he is being taken from a warm home and put in a cold ambulance.

-Verity James, Woodingdean