Just wanted to share my experience when my Prusik jammed on a 20m overhang. The video died in the end, but eventually, my mates had to lower me a knife using a miraculous old sling they found and I had to cut both Prusiks off. I would caution against anyone using a Prusik on a descent. It’s important to know it for an ascend, but definitely dangerous otherwise. If there was flowing water, I would have been dead.
Also, I escaped the harness shock syndrome, partly because I was horizontal most of the time. In the video, you can see me jam my hand between the ropes to stop from flipping over, as I lost strength surprisingly fast. After i dropped my pack, I used my mate’s cord to create a makeshift seat with my feet on my safety sling, so that I did not remain vertical.
No matter what I did, I just could not loosen the top Prusik even though it was unweighted. The Moral of the story: back up with the French (not sure about this in flowing water), go with mates, keep the spare rope up the top, keep a knife on your person, don’t stay vertical and always, always, Always, Keep the Stoke. It is a beautiful Canyon, an incredible day and one I definitely look forward to rocking on again.