Desmond was used to the darkness, a complete lack of light and heat. That hint of loneliness and hidden malevolence that Desmond always felt within him.
The darkness had grown with each sin he committed, further fueled by his desire to protect those he loved. But there was an occasion, a moment in Desmond's memories, where he was wholly plunged into darkness... the day he died.
Experiencing death was quite a traumatic experience for anyone; no matter how strong his resolve and character, Desmond was no exception. Desmond's psyche was never one of the most stable things in the first place, so that memory stayed fresh inside his mind.
Now, Desmond felt that same darkness consuming his world and his mind, that nauseating cold feeling that wouldn't disappear. Then the memories and emotions poured over him like a waterfall.
