The subject's state could be compared to somebody in certain phases of sleep or in a coma. Not the same as those, but quite close. A quote in the article describes her as being 'still awake', but I wonder what that means.
It's not like the subject became a zombie. According to the very brief description, she just became completely unresponsive, didn't do anything, and had no memory of what had happened.
In contrast, patients in a persistent vegetative state are awake, but not aware. It sounds like the researchers may have replicated this state of consciousness, which would imply that the claustrum is important in awareness, but perhaps not as critical in wakefulness, at least in this particular subject (keeping in mind that her brain is already abnormal in some sense due to epilepsy and neurosurgery that excised the left side of her hippocampus).
This paper has a nice review of the topic: http://www.coma.ulg.ac.be/papers/vs/2005_VS_TICS.pdf
I suppose both physical and neurological observable processes that as we know define 'sleep' and 'awake': her eyes were open but with a blank stare and so on, and since they said she did not exhibit neural signs of epilepsy, she was wired to an EEG, so brain patterns would possibly not be matching any phase of sleep but wakefulness.
That's all that could be inferred from the article, which is honestly quite thin and sensationalist.
she gradually spoke more quietly or moved less and less until she drifted into unconsciousness.
That part of the process sounds very similar to someone undergoing anesthesia, or simply falling asleep. Though there are obvious differences.
So maybe that's what it feels like? Some people remember the feeling of going under, but maybe not the last few seconds of it.