As others have pointed out, it probably is not a good idea to use pressurized air in this case . I myself received a lung over expansion injury in shallow water. In 1992 I was diving off the coast of Spain in rough seas. The dive was over and I was waiting my turn to enter the boat on a rear ladder while trying to avoid being brained by it. I had just removed my fins and grabbed the ladder at the bottom of a trough in the water when I was yanked upward by the ladder as the boat traveled to the peak of a wave. I was pulled up from about 3 to 4 feet fsw to the surface rapidly. It felt like a million pin pricks all over my lungs and thankfully never developed into anything more than a nagging cough for several weeks. In short, if you can't control your depth don't use pressurized gas to breath. I was a fairly new diver then, but I learned my lesson on boarding boats in the open ocean.