Vestuvius of the Sleepy Marines curled up in his Battle Bed, attended by servitors who awaited with warm milk and cookies to send him drifting back to sleep should he awake unexpectedly. Consciousness left him within minutes, and training kicked in as he grew aware of himself once more, garbed in powered armor and carrying a bolter. They were what was most familar to him, but he could easily rearm himself for whatever task was at hand; he was a Dream Warrior, one of the veterans in the fighting at the edge of the Immaterium where dreams drifted by.
A dark room surrounded him, the same bunk which he left, but desolate, empty of all life, even biomechanical creations such as servitors and servoskulls. With a few steps, he approached the door, but instead of opening out to the rest of the barracks, a dark, shimmering room appeared, filled with floating doorways of the Shared Slumber. The doorways led to all sorts of strange, unusual, and even horrifying places, from dark forests to endless lands made of squirming, twisting body parts, crying silently, down to the Red Maze beneath it all, unmappable and filled with horrible daemons who stalked its passages and stole a person, locking them away in some hidden place in the Shared Slumber, lost for eternity.
He was alone, but in their dreams, the Dream Warriors were always alone. But it was no matter. The doors drifted past, each offering a pathway towards worlds unheard of, some pristine, some filled with gibbering madness Daemons can only dream of letting loose upon the Materium. But none of those were his destination. Instead, a black door with a crescent moon and stars swiftly advanced towards him, opening without a sound to envelop him whole.