I've dived the Sinai's Blue Hole, so it's wild to see this on HN. It was an intense experience. Our dive instructors warned us of how deadly the site was, and

I've dived the Sinai's Blue Hole, so it's wild to see this on HN. It was an intense experience. Our dive instructors warned us of how deadly the site was, and the various hazards. But the dive itself was unique compared to other deep dives I've done. I would describe it like parachuting, slow motion, into the bluest blue. By the second, the sunlight got dimmer and the blue got bluer. It was disorienting if you looked in any direction besides the crater wall. At about 25m down, I looked up and realized we were too deep to reach the surface quickly. That triggered my panic reaction. I started hyperventilating into my regulator, and had the urge to spit it out. But knowing that would be literal suicide, I managed to override it. I felt like given a few minutes, there was a strong chance of getting my panic under control, but I thought, "why take the chance?" Also, the dive plan was to continue to go deeper, and if part of my panic was due to nitrogen narcosis, it was only going to get worse. It wasn't worth it for a recreational dive. So I gestured the "up" signal to one of the instructors, and she immediately worked with me to do a controlled ascent. I spent the rest of the time doing a shallow dive along the crater wall, which was much more relaxing.