Had a double Endoscopy about a year a go as a result of being very very anemic from my severe adverse reaction to a flu jab, where they said my anemia might be caused by blood loss. Yes, the camera is on a 0.5" flexible cable, it has to be so they can pass tools down it work on you taking samples and also in my case the injection of water to raise a polyp for removal and then removing it.
You have to use industrialist strength laxatives the night before to 'clean' the system. I was offered heavy sedation or nothing. I had a very bad reaction to barbiturate based sedative for the removal of two wisdom teeth, many years a go and swore I would never go through that again. So had the camera down the throat with just a throat spray, gaged momentarily as it went past my windpipe but was fine after that. Watching on the monitor makes 'interesting' reality TV.
Then had camera the other end which was very slightly painful at times where the have to navigate the camera round relatively small radius's in your intestines, but this feedback on the awkward bits did help the nurse operating the camera and the doctor moving my intestines about to help the camera move. They found a polyp right on the junction between my large and small interesting, which was very awkward to remove. Only watched the second half of the procedure, including the removal of the polyp as I was laid on the right side to watch the monitor.
At the end of it the doctor did congratulated me on being so calm and collected, saying he wished all his patients were like this.
So, man up, remain calm STEMO and you will be fine. I'm sure you've had worse up the jacksie from Gixer.