Yeah, he did. "... for richer, for poorer, in sickness and in health ...".
You are really working yourself into a tizzy over nothing. A colonoscopy just is no big deal.
Now the prep before hand .... oooh, YECK! diarrhea to the point of pure yellow "water", mebbe some nausea, a burnt bottom if you don't wash your bottom after each "trip" w/a warm wash cloth, or whatever ... NOT pleasant, but also nothing to get in a twit over. Worth a few mumbles, grumbles, etc.
You just tell your gastro and the staff that you are scared, that you don't want to feel or know anything, you want to be OUT OF IT. And they'll see to it that you are deeply sedatated. You will wake up when its over asking when they are going to start.
Some people are like Slinkies... Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.