Today, I had a hyperbaric oxygen treatment.
I spent ninety minutes at two-and-a-half atmospheres of pure oxygen with two five minute breaks of two-and-a-half atmospheres of 'medical air' to prevent oxygen toxicity. It took fifteen minutes to go from one atmosphere to two-and-a-half, and fifteen minutes to go back. That is a long time to lie in a clear acrylic tube the size of Fat Albert's coffin.
I survived. I watched a movie. I will do it again tomorrow.