Final answer:
During the primary assessment, if a life-threatening emergency is identified, the appropriate action is to call for emergency medical assistance immediately.
Step-by-step explanation:
During the primary assessment, if you determine that your patient has a life-threatening emergency, the appropriate action to take is to call for emergency medical assistance immediately. This is because in a life-threatening situation, timely professional medical intervention is crucial for the patient's survival. Administering first aid or waiting for the patient to stabilize may not be sufficient or timely enough to address the emergency.