Fascinating. The end of the CNN article about this is incredible:

> Richard Harris, the Australian anesthesiologist, was one of only two cave-diving anesthesiologists in the world. "I didn't think it would work at all," Harris told National Geographic. "I expected the first two kids to drown and then we'd have to do something different. I put their odds of survival at zero."

https://www.cnn.com/2019/04/04/health/thailand-boys-cave-ket...