If Number 6 wasn’t sedated, but was feigning it, it would be expected of the doctor-Number 14 to realise that, and consequently inform Number 2. But on the other hand, if Number 6 wasn’t sedated perhaps the doctor chose to keep that to herself, thereby using Number 6 to help her achieve her own ends against Number 2. After all he had forced the doctor to use her new developed drug on Number 6, when it hadn’t been tested on animals, let alone humans, otherwise Number 2 would see the drug proved on her!
This train of thought came about by the doctor’s reaction towards the end of the episode. Number 2 said that the doctor’s drug had failed, but no, Number 6 had succeeded. That was something the doctor seemed to be pleased about, judging by the expression on her face, the tone of her voice, that Number 6 had brought about the downfall of Number 2.
And the drug? The third dose had been diluted by Number 6, so what might be the effect be on Number 6? Certainly diluted drugs do have their dangerous side effects. However in the episode it merely lessened the affect of the drug, and helped him control the third dream sequence.
Be seeing you