What should be the immediate action when a passenger shows signs of a cardiac event?

When a passenger exhibits signs of a cardiac event, the immediate use of an Automated External Defibrillator (AED) if available is crucial. Cardiac events can escalate quickly, and the timely use of an AED can significantly improve the chances of survival. The device is designed to analyze the heart's rhythm and deliver an electrical shock if necessary, which can help restore a normal heart rhythm during a cardiac arrest.

In such emergencies, acting quickly is vital, and the AED provides clear instructions for use, making it accessible even for those who may not be trained in advanced medical techniques. While monitoring the patient is important and providing reassurance can help in some situations, those actions alone do not address the life-threatening nature of a cardiac event as effectively as using an AED.

Providing water is not advisable in this scenario, as it can pose a choking hazard and may not be safe depending on the passenger's condition. Asking for medical supplies might delay critical intervention and is not the most effective immediate response. The primary goal during a cardiac event is to restore normal heart function as quickly as possible, which is best achieved with an AED.