I dunno, on the other hand it would seem our prison systems contain a surprisingly large number of extremely eloquent and level-headed people, to judge by some logs on other SCPs. I've said before that it's always a little eyebrow-raising when someone ostensibly recruited from a place it was assumed no one would miss them rattles off answers like "Vocalizations are emanating from approximately twenty to twenty-five meters in a descending direction, Control. Do you wish me to proceed?"
I agree it's a matter of personal choice on the part of the author, but on the whole I think it's a bad idea to attempt to extend some amount of the clinical tone to D-class, or even in every case the researchers. I'd say the original's fine, but "nothin" and "sittin" should be "nothin'" and "sittin'", since I believe that's the proper way to convey an accent via text.
The "correction" just sounds way too polite, in any event. D-class are usually portrayed as fairly aware of their status as lab rats. Saying "Doctor, I would have appreciated a TV or a magazine" makes me picture some guy in a prison orange jumpsuit and a bowler hat, monocle carefully in place and pinkie extended from his tea cup, giving the camera a mildly scolding look.
Edit: Dude all sitting there, sighing in a much put-upon manner and shaking his head. "This really is a most perturbatory waste of my time. Why, today D-18395 was going to complete my ritual scarification in the shape of a crumpet. My dear mum had one just like it, you know, when she went to the 'big house' in her own day." Dammit now I can't get the image of Extremely Refined British Delta out of my head.