Hey, just wanted to leave some quick feedback on this story while I had the time. I know you asked me to take a look at this like ten million years ago but I've got a little time right now, so I thought I'd comment in case you were still looking to do something with this.
But anyways I actually thought this was pretty interesting. You did a good job of building up the suspense of what exactly is going on in the facility without coming off as exploitative or hokey. I feel you moved the story along at an acceptable pace (though you could chop it down a bit if you wanted for the sake of succinctness), and the way you described the procedure with the inmate kept my interest. I like how no real damage is being done to the inmates except for the mental aspect. Also of note is that despite the unorthodox perspective you chose, it never came off to me as being awkward or silly. I didn't find any grammatical errors or wording issues (unsurprisingly). All in all I found what you currently have in good shape.
I will say though that the revelation that it was all for the sole purpose of the scientist's studies was slightly odd to me. Perhaps I was expecting something a bit more insidious, but after reading the ending I was like, "Oh, that wasn't as bad as I thought it'd be." It sort of leaves me wondering how exactly the protagonist feels by the end of the story. Anyway, that's all I can think to say for now. Hope it helps a bit!