This reminded me of a memory I have from when I was about 7 or 8. I was at my grandparents house with my sister for the day like we often did over the summer. We were swimming in their pool which was a rectangular pool with a slant, 7 feet in the deep end, my sister was on the opposite end of the pool in the shallow end. Now this whole thing only lasted a few moments. I was just treading around by the diving board and I dipped under about 2 or 3 feet. They had the kind of pool where you could open your eyes and it was fine so as I usually did I opened my eyes and briefly played as a mermaid. All of a sudden time seemed to slow or stop being relative and I took several deep breaths. Confused and shocked after reaching the surface again I didn't tell anyone but I knew it was real. Even tho it only lasted seconds I vividly remember feeling the movement in my throat and lungs as I took those breaths. I don't know if physics suddenly and temporarily changed or if I experienced a glitch but I still remember it to this day 12 or 13 years later.