The rescuer must press the device’s “Shock” button to deliver the shock to the victim of cardiac arrest. This ensures that no one touches the victim before the device delivers the shock. If the victim comes into physical contact with someone standing next to them, that person could receive a strong electric shock involuntarily. The semi-automatic defibrillator allows the rescuer to make the final decision on shock delivery. This is because it can take into account the environment around the victim, unlike the device.