I needed to start by getting my combat roll back. After the Usu, I had lost it, or at least it had become totally unreliable. Sometimes I’d manage to get upright weakly, but other times, I’d get partway up, plop back over, immediately revert into panic mode, and pull my skirt. When that happened, Rob had told me, “You’ve got to keep trying. Sometimes, it takes three or four tries. You have a lot more oxygen than you think, but you have to get the intellectual part of your brain talking to the primitive part, and the intellectual part needs to rule.”

I spent the morning warming up by paddling around the top pool. Seven giant pumps pulled the water from the bottom pool back to the top, and the water surged out through mesh screens. I paddled hard against the force of the jets, like paddling upstream against a powerful current. I practiced my roll and then worked with Casey on the various commands.

After a couple of hours, there was no way to delay any longer.

“Ready to do this thing?” Casey called out.

“I guess so,” I called back, and we floated from the calm pool into the channel. A few ripples rolled over my boat. The first rapid was called Entrance Exam. I went through the first wave. I was expecting a warm-up, but it smacked me hard, and I was instantly over. I managed a weak roll, but the wave had shoved me far to the right.

I bobbled sideways over a man-made rock, just inches beneath the surface, and flipped again. That was too much for my nervous system. The intellectual side of my brain didn’t even make an appearance, but the primitive side screamed and reacted. I pulled my skirt, coming up sputtering with waves crashing over my head. I tried to take a breath but instead swallowed a huge gulp of chlorinated water. I wound up swimming through four more rapids, finally washing into a giant pool a third of the way down.

Rob was there beside me. “Grab my boat,” he called, and he towed me to a small island between the channels. I sat on the edge of the pool for a good forty minutes with my face in my hands. I was shivering under my dry top despite the warm day. In my swim, water had hammered into my ears and down my throat, and I felt dizzy and sick. Palms pressed against my eyes, I was in the Usumacinta again, paddling for my life.

“I know you don’t want to hear this,” Rob said, “but the best thing right now is to get back in your boat. We’ll take a break, and we can chill out for a while, but you’ve got to get back in.”