I saw this the other day, and something I don't understand about it is that ~40 years ago (so its dimly remembered) I did SCUBA training and oxygen toxicity is

I saw this the other day, and something I don't understand about it is that ~40 years ago (so its dimly remembered) I did SCUBA training and oxygen toxicity is definitely a thing. So how is it that having a partial pressure of oxygen over a certain level while diving is toxic (delirium causing, which is especially dangerous underwater) but in a hyperbaric chamber is theraputic?