That's CNN, so I'm really hoping it's sensationalized and blown out of proportion...key word is "hoping."
Where I live (South Australia) so called Pill Mills like this were a lot more under the radar, so to speak, than the ones shown in that video, but essentially they still operated in pretty much the same way. The one I used to frequent as a former addict was pretty much divided into users and dealers. Users could turn up and get a limited amount of whatever pill they fancied (Benzos, mainly), so long as they at least went through the pretense of a 'consultation'. Dealers were trusted patients who paid a few hundred dollars, cash up front, to keep things off the record. They would then sell the pills out on the street (at around $5-10 per pill, depending on what it was), and give a percentage of the profits back to the Doctor. This particular clinic had at least ten full time 'dealers' on the books (as in they were pretty much treated, and referred to almost as employees') at one stage ('full time' as in they were there for scripts at least once a day).
Basic level users could sometimes get stuff off the record as well, usually a bit extra than what they'd otherwise be prescribed (40 pills of Xanax, as opposed to 20 of Serepax, for example, maybe a couple of vials of Pethidine thrown in for good measure), if they were willing to provide sexual favours. Usually within the first 3-4 visits, once you'd been scoped out, you found out whether the Doctor was willing to pay for services rendered when he locked the door and strongly implied that if you'd just like to hop up on the exam table *nudge nudge wink wink*, there'd be a little something extra in it for you.
In my experience, just speaking from my own observations as a past client of these sorts of clinics, there tended to be 3 main types of Doctors you came across that were pulling scams like this. Either a: Doctors who just didn't give a rat's, and were basically criminals with medical licenses, b: Doctors who had serious drug habits of their own (I have sat through a 'consultation' with a Doctor on the nod to the point of his head basically being on the desk, with a nice stream of drool coming out of his mouth, whilst a freshly used, uncapped syringe lay in plain site in a wash basin nearby - and of course none of his patients are going to care, or report him, because, hey, we're all addicts too, and this dude keeps us supplied with happy pills), or c: Doctors who have gotten caught up in the image of the hip, and trendy Doctor with a rock star lifestyle (fast cars, fast women, lots of partying).
Trust me, those 'Pill Mills' are a reality, and for all CNN's apparent beat up and sensationalistic journalism, what they showed in that video is pretty much the way things go down. It's dark, it's degrading, it's ugly, and I am so very, very glad to be out of it.