A horrific death-defying experience for a strong swimmer. Even though the guide provided ample safety and risk information and training, what happened was not expected. At the first level 5 rapid, the raft dropped down the 3-metre-high rapid, flipped up and over due to the force of the water resulting in the 6 of us either thrown into the vigorously turbulent water or holding on under the raft. Due to the turbulence, I was held under water for about 30 seconds not able to see or determine which way was up. Eventually I surfaced and caught my breath, only to find myself soon dragged underwater again by the fall of the second level 5 rapid. After surfacing and catching my breath a second time, the experience was repeated at the third level 5 rapid. I eventually entered a fast moving rapid-free stretch of water where I was able to see and reach for a rope attached to a raft and pull myself to the shore, gasping for air and coughing up water I had swallowed during this ordeal of several minutes and several hundred meters. Luckily the 6 of us were left without series injury, however we were very much in shock. Unfortunately, the only way out of the canyon was to return to the raft and complete the journey that included 2 more level 5 rapids, which we managed without further incident. I would recommend this activity for only those who are extremely strong swimmers and are willing to take high risks.