It just means the window into this material world and all its properties (including time), as provided by the biological machine of the human body, is closed when we are not physically conscious. If our conscious awareness derives from our soul's awareness of physical brain activity, then when that activity ceases, so does our awareness of that activity.
If that were the case, we wouldn't wake up in the event of loud noises, surely? In order to have the conscious mind prompted by external stimuli to awaken, it has to have some degree of connection to the material world when unconscious.
I'm fairly certain that whilst in everyday terms we can treat states like 'sleep' and 'unconsciousness' (and, to a degree, 'comatose') as interchangeable, in purely neurological terms they are quite distinct: even within sleep there are several different neurological states in which that degree of 'connection' between the conscious and the outside world varies.
O.