My first thought when watching the coverage was that those 13 people are going to die. I think one of the biggest jobs those rescue divers had was keeping the children calm. Whoever is in that litter has likely spent a very, very long time in freezing cold water. Those emergency blankets, or space blankets, do a decent job at retaining body heat. They basically bundled these children using a flexible plastic stretcher. In the way that these divers navigate appears to be using a static line that was most likely bolted into the rock face and anchored permanently, or semi-permanently, in that way so that the divers were able to simply follow that line. The person on the left has basic open-circuit scuba equipment. You can see that silver air cylinder. And the person on the right actually has what’s called a “rebreather.” It actually allows you to dive for much longer than a standard scuba system. So the reason to have two tanks: One is redundancy. If say there’s an equipment failure with the first tank you could switch your regulator over and breathe off the second tank. The other reason would be to extend the duration of the dive so that you could switch over to a second tank if you’re running low on air on air on the first tank. It seemed like a really impossible situation. So I was absolutely amazed that they got everybody out and that the only — that they only suffered one fatality and that that was one of the rescue divers.