By this episode, we have an idea about the layout of the interaction between some unspecified future and the present times. We have seen some action unfolding, we got used to a set of characters in the inner circle and around them, and we have started to accept an alternative reality.
Room 101 provides an unexpected setting with the majority of the characters being confined in a surreal setting and being questioned about their background. We never learn who the antagonist might be, but we have the chance to see four out of five of the main characters act in a severely confined setting. Deprived of most of the tools actors have at hand, the team members help to create an extremely unsettling atmosphere that opens numerous questions about the forces there be.
One episode that opens several dimensions to the plot of the series. Subtle means in setting the stage such as the confinement into cells and into wheelchairs, and the ominous thin film of water over the pathways in the nondescript detainment facility add greatly to an eerie atmosphere of doom.
Don't watch this one if you think you might be claustrophobic.