I was learning to use a DPV during my advanced course. I check my air regularly, and when I hit my ascending point, I let my instructor know. He signalled ok and to keep following him, so I did. We kept going for a while, and now my gauge was reading about half of what it did when I first let him know, so I let him know again that it was time to go up, now! He again signalled ok and to keep following... so I did. I was getting really nervous at this point, and was thinking to just head up by myself. A few moments later, a breath took a bit of effort to pull out of the reg. I looked down and my gauge read empty. I panicked. I tried finning faster to catch him (he was only about 10-15' in front of me), so I could use his octo. With both of us on DPV's, I was not going to catch him. I took the reg out of my mouth and tried to scream his name, a really moronic idea, but what can I say, I panicked. I realized the danger I was in and that I was panicking, so I got my head together, and started ascending. I kept the reg in my mouth, took large breaths, and slowly let bubbles out on my way to the surface. I think I only took 3-4 breaths on my way up, as I was deathly afraid of running out of air completely. It was very hard to draw those breaths.
When I reached the surface, I waited for a short few moments, then started swimming back to the beach where I waited for him. He finally surfaced and saw me standing on the shore, made it back, and explained that he was aware of my situation and he was just about to stop to give me his octo to finish out a safety stop, but when he turned to look for me, I was gone - so he circled around a few times to find me before surfacing. I'm glad I went up myself and I was mad we didn't go up sooner. I learned a valuable lesson that day, and I'm glad it happened early in my diving career. It made me a much wiser diver, and I pay critical attention to a lot more things now. If I need to end the dive and my team won't, well sorry to say, but I'm out, see ya! I like what is preached by cave divers and by people on this forum: When someone thumbs a dive, the dive is over. No ifs ands or buts about it. I don't care if it's a slight ear issue, air issue, spooked out for a second, whatever. The dive is over with no questions asked or explanations needed (although I would prefer an explanation so I could learn from the incident - but by no means would it ever be critcized... ever!) . The underworld is a deadly environment and things can go bad very quickly with horrible consequences.