The entire story is a stealth crossover with Neil Gaiman's Sandman
- Link for those unfamiliar with the comic. Or at least that's what I personally prefer to believe. The sandmen are actually Dream's magic sand (already known to have carnivorous properties when not kept on a tight leash). It's manifesting in the real world because the Morpheus machines are cutting into Dream's sovereign territory. The Doctor knows this. The whole Morpheus speech he cribs from Macbeth at one point is him begging Dream to call off the dogs and promising to set the situation right. The whole eye-gunk explanation is just something he came up with off the top of his head so he doesn't have to explain the Endless to everyone (which would take too long and be boring.)
- Additional Fridge Brilliance: Rassmussen (or is it one of Dream's nightmares?) isn't really making the video to spread the sandmen. He's putting together a scary story to make sure humans stop using the Morpheus machines. That's why the Doctor doesn't stop the signal from going out. (Why a story? Because stories are kind of Dream's thing.)
The whole encounter is actually a scam by...
- ...the Vashta Narada. We know from events in the Library that they're not unintelligent, that their natural form is that of dust, and that they're capable of animating human remains as large as bones and making them walk around. Surely it's not beyond their abilities to animate a bunch of tiny flecks of human sleep-dust and form them into humanoid figures! And they have the perfect motive to enact such a scheme: they wouldn't want the sleep-pod technology to spread, because ever-waking humans wouldn't need darkness anymore and would arrange to fully illuminate every planet they colonize. Fearing for the shadows they need as a habitat, the Vashta Narada staged the whole incident to scare humanity into abandoning Morpheus wholesale, for fear of non-existent "sleep-dust monsters". Now they can broadcast their video, lend it credibility by nomming some more humans wherever people are stupid enough to watch it, then sit back with full bellies as sleep-pods all over the solar system are consigned to the scrapheap.
- Note that this explains why the lights are so low or non-existent in a station where nobody on board sleeps, so shouldn't have needed the ability to dim them: the VN keep it that way so they can move around freely. It also explains why Rassmussen keeps on filming and uses the footage in his broadcast, despite how the Doctor's and Clara's presence surely wasn't accounted for in his intended scenario: both Chopra and the Doctor voice some really scathing opinions about Morpheus, which he opted to make use of even if things like the psychic paper would seem like a Plot Hole to the video's in-Verse viewers.
The gravity generators didn't fail, as in switch off.
- Rather, they "failed" as in got stuck on maximum inside the station rather than negating gravity outside of it. Hence, the interior Gravity Screw effects.
The Doctor was able to intercept the broadcast...
- ...but he did not stop the broadcast, as he felt that would tip his hand to soon to Rasmussen, who no doubt had a back-up plan. Instead, he edited the broadcast, adding intentional inconsistencies and errors in continuity and story logic, even lampshading his edits a few times by pointing out that "This doesn't make sense!" In doing so, he encouraged anyone who watched the broadcast to think about what they were seeing instead of simply accepting it at face value, and that heightened synaptic activity would be enough to ward off the effects of the Morpheus field within the broadcast, thus mitigating and even undoing any damage that Rasmussen had intended.
- Or maybe he simply added that flash of title-credits to the feed, which contained encoded data of its own. Out-of-Verse, that hidden data is the legally-mandated credits for the episode, but in-Verse it's a signal that negates the effects of the remainder of the broadcast.
The Morpheus pods leave users hungry.
- They seem awfully similar to the Enertron modules from Chrono Trigger, which provide a night's rest in an instant but do nothing to relieve hunger. And of course, generating demand for processed food products and such wouldn't be an unwelcome side-effect for corporations trying to wring profits out of their employees.
- Also generating demands for calcium and joint-health supplements, as sleep is when the human skeletal system normally tackles the repair-work for millions of microfractures and collagen-fiber breakages suffered during a normal day's activities.
