Even firemen are taught thing like “You arrive at a burning building. You hear screams inside. You do not go in there without authorization." Or "you are called to an emergency scene. People are reported down. You do not approach until police arrive."You need a plan, and you need coordination. If individual firefighters go in half-cocked, they risk not just their own lives but the lives of the people who now have to go in and rescue them.
But there are times when emergency response personnel can use their own judgment instead of waiting for a scene commander to arrive.