Aside from fires, which of the following is a type of emergency situation security personnel might encounter?

Medical emergencies are indeed a type of emergency situation that security personnel might encounter. Security officers are often tasked with maintaining safety and responding to various incidents that may arise on their premises, and medical emergencies can be critical situations requiring immediate action. These may include scenarios such as someone suffering a heart attack, a serious injury from an accident, or other urgent health-related issues. In such circumstances, security personnel may need to apply first aid, call for medical assistance, or facilitate the arrival of emergency services to ensure the health and safety of individuals involved.

In contrast, routine traffic stops and end-of-shift reports do not pose immediate risks that necessitate emergency response from security personnel, as they are part of standard operational procedures rather than emergent situations. Social gatherings may require supervision for safety reasons, but they don't inherently represent an emergency unless an unforeseen incident occurs. Therefore, medical emergencies stand out as the clear answer due to their potential severity and the urgency required in response.