I had a a scope last year that I woke up during, I can remember being in pain and them telling me to breath. Then they knocked me back out. So it is possible to wake up and remember, as I don't believe they "fully" knock you out. Like they would if you were having surgery. The first scope I had I didn't remember a thing, and went well. But it can happen, and for my next scope I plan on talking to the doctor about
it before hand. I don't ever want to wake up during it again.
As for the prep they always make me drink that half go-lytely stuff. Yuck, I have a hard time keeping it down and getting it all in. They need to seriously come up with a better way to test us. I completely dread doing any of it again, and will probably try to push it off a few more years if I'm doing well symptom wise.