I shared air with the guide in Fakarava, French Polynesia. There was four of us, the guide, myself and a couple who were former DM's. We dropped into the blue of Garuae Pass. We proceeded down to 27m and drifted our way up to 13m to get over a reef lip, then down to 20-22m for about 15 min. Just after the 13m, she checked everyone's air and decided I needed to be on her octo, as she knew we would go into mandatory deco; that was in the dive plan. At some point in the 15 min, I switched back to my primary. We finished off the dive with a 15 min stop at 5m. I had 50 bar at the end. Total dive time was 60 min.