What should you do if air is rushing out of the mask-mounted regulator when you open the cylinder valve?

If air is rushing out of the mask-mounted regulator when you open the cylinder valve, immediately close the cylinder valve to stop the airflow. Check the regulator and mask for any obvious leaks or damage. If you are unable to identify the issue or if the problem persists, do not use the equipment and seek assistance from a qualified technician or follow your safety protocols for equipment failure. Always prioritize safety and ensure that your gear is functioning properly before use.