I am SO disappointed with that episode (Sleep No More).
The annoying thing is that there were some good ideas in there, principally the Morpheus machine. And I did like the anti-capitalist strain of the story. But sadly, the whole thing just never really came together.
I was thinking that maybe the Morpheus machine was blurring the lines between dream and reality or something like that, but no. It was sleep-dust coming to life, for no apparent reason. Sleep dust which can take humanoid form, and/or float in the air being invisible cameras. Sorry, but I just can't swallow that level of ridiculousness.
Hang your head in shame, Mark Gatiss!