My wife and I were on a two-tank twilight/night dive. On the night dive, my wife, who is a new diver, entered the water first. I geared up quickly, checked my regulator and BCD inflator but failed to check my submersible pressure gauge (SPG). I entered the water, and the group (led by a divemaster) quickly descended. The divemaster swam off toward the spot where the group would watch the manta rays. I brought up the rear of the pack, since I descended more slowly. My wife was about 30 feet ahead of me.
I noticed my regulator breathing much harder. On the second breath, I only received half a breath and knew my tank was empty. I rapidly decided between swimming to my wife and swimming to the surface, and headed for her. She was swimming away from me; I caught up to her but was already feeling air hunger when I reached her. I grabbed her octopus, but I put it in my mouth upside-down and was initially unable to get air from it. After several more tries, I got a breath of half water, half air, finally obtaining just enough air to surface.
Signaling to my wife to surface, we made an emergency ascent. On surfacing, I dropped my weights, and she inflated her BC. (I was unable to use my power inflator because the tank was empty.) We shouted for help, and eventually a snorkeling instructor came to our aid, guiding us to another boat, where we left the water. Neither of us was injured, although I did aspirate some seawater.
Our boat crew had been responsible for setting up everyone's gear and changing tanks between dives. We determined the crew had given me a nearly empty tank, and I did not detect it since I had not checked my SPG.
Omitting the predive check could have cost this diver his life. The predive check will verify that there is enough breathing gas in the tank and that the regulator works fine.
Why did this dangerous omission occur in this case? Being married does not automatically establish the perfect dive-buddy relationship. Buddy-diving rules should be recited before each dive regardless of who you are paired with. The buddies should enter the water at the same time after making sure that both went through the entire predive checklist. Once in the water, the predive check must be completed by inspecting each other's equipment for potential leaks.
Buddies who separate before entering the water probably will remain apart during the dive and will not be able to provide each other with assistance. In this case, it was just luck that the diver managed to catch up with his wife before running out of air.
Picture is not actual couple---taken from the net.