NEWS YOU CAN USE: Here’s What Happens When You Have A Panic Attack Underwater. If you’re prone to panic attacks, don’t scuba dive.

When I did the Popular Mechanics rebreather test dive some years ago, the “contralungs” on the rebreather were much smaller than my actual lungs. (They were mediums; I’m like an extra-large in lung capacity). That meant that I couldn’t get a full breath, and at one point I was aware of a powerful desire to spit out the regulator and take a deep breath. Being a phlegmatic type, I’m perfectly capable of feeling a powerful desire and not acting on it, but it was the first time I understood how that sort of thing might happen to people.