In the event of any fire, crash, search and rescue, natural disaster, national peril, radiological hazard, or other calamitous emergency—

(a) No person may impede or hamper any officer or employee of the United States or any other person who has emergency authority;

(b) No unauthorized persons may congregate at the scene of the emergency; and

(c) Each person present shall promptly obey the instructions, signals, or alarms of any peace officer, fire or crash crew, or other authorized person, and any orders of the Commander.