The person with the highest medical cert/license will be the one in charge (and responsible) when medical care is performed........
Don't believe this for a second!!! Do you really think an OB doc is a better choice for you in a trauma emergency that a seasoned paramedic? I can't tell you how many docs I have had removed from my scene when they were nothing but trouble. Put a seasoned paramedic in and ICU and he or she will be equally helpless!!! Everyone has their role and good people know it and stay the hell out of the way.