The following is excerpted from the International Amateur Radio Union (IARU) publication IARU Emergency Telecommunications Guide. (2015) A PDF file of the document can be found here.
As important as what you are, is what you are not. There are limits to your responsibilities as an emergency communicator, and it is important to know where to draw the line.
You are not a “first responder.” Except in rare cases of chance, you will seldom be first on the scene. You do not need flashing lights and sirens, gold badges, or fancy uniforms.
You have no authority. In most cases, you cannot make decisions for others, or make demands on the agency you serve or any other agency. The only decisions you can make are whether to participate or not, and those affecting your own health and safety.
You are not in charge. You are there to temporarily fulfill the needs of an agency whose communication system is unable to completely do its job. They tell you what they need, and you do your best to comply.