Adrian feels like drowning in deep, deep water.
It's cold and dark - like a huge empty void.
There is this dense mass of mist that is hauling in a dreary and bizarre sort of feel. There are distant voices and faint noises. There were a lot of movements for some time, but eventually, they all died down. In the end, there are only fills of emptiness and heavy silence.
Then, there are these vivid images that suddenly take form before him.
Adrian tries to figure out what they are rather than why they are there. He peers through each one of them until he is pierced by a great deal of reminiscing all of the sudden. Now, he has to rely on what he is feeling instead of what he thinks. If he were to deny their existence like what his brain was telling him to, they might vanish.
These are flashbacks of his past - is what his feeling telling him.