What should a diver do if they experience an out-of-air situation?

In the event of an out-of-air situation, using a buddy's alternate air source or performing an emergency ascent is crucial for ensuring safety. When divers are trained, they learn that one of the fundamental principles of buddy diving is to assist each other in emergencies. If a diver runs out of air, they should immediately signal their buddy and switch to their buddy’s alternate air source. This quick action allows them to maintain buoyancy and avoid diving-related injuries.

Additionally, if no alternate air source is available and an immediate ascent is necessary, it is important to perform an emergency ascent. This ascent needs to be controlled and done at a safe rate to minimize the risks of decompression sickness or lung over-expansion injuries.

Options like swimming rapidly to the surface or waiting for rescue do not effectively address the urgency and risks associated with an out-of-air situation. Rapid ascents can lead to serious injuries, making it critical for the diver to use their buddy support as the primary and most effective method of handling the emergency.