Here is the progress so far on the story for this challenge. I kinda bs-ed most of the details pertaining to ship function, because I really haven't read any 40k lit about that. I'm planning to go for about six pages, but we'll see if I can really tease that much out of it.
The Toll of Failure
“We have our heading, courtesy of the Arch-Magos,” The Marshall boomed to the command deck, “Lay in the course, sync with the fleet, and let us be about it. They tell me the voyage may take weeks. I know I’m not the only one who would see this system put well behind us.”
The Marshall didn’t turn from the viewport as he made his last statement, but Mahlur knew that the Chapter Master referred to him. He ill concealed the angry grimace that pulled at his face, and turned and left the deck to seek the solitude of his own quarters. A few corridors clear of the command deck and any living presence but a couple of passing servitors, he allowed himself the release of slamming a gauntleted fist into the bulkhead plating as he passed. When at last he reached his quarters he sunk into the bench along the rear wall, and tried to recite some of the focusing litanies the Wardens taught. The peace he hoped for did not come. Though he had escaped the perceived judgements of his brethren, their whispers and glances, they were replaced by the tumult of his own mind; his mistakes during the challenge, the taunts of his opponent repeating again and again, filling his ears in a way that could not be silenced. When it finally became too much he lurched to his feet and let a guttural roar of impotent rage tear from his throat.
Panting as the anger subsided, the blood pounding in his head seemed to drown out his thoughts, he stood, looking around the room and letting the feeling ebb from him. After some time, minutes probably, but it felt longer, the ship’s captain spoke over the ship-wide vox.
“All hands to warp stations. The Reilios enters the warp in five minutes.”
Mahlur slumped, and began removing and stowing his armor. He lay awake on his slab when he felt the tell-tale jolt of the ship breaching the warp, and allowed the otherworldly hum of the geller field generator far below to guide him to sleep.
Hardin had been attending the bulky and demanding generator engines for only two days without sleep. Others had gone longer in the past; even he had, on occasion. So he was sure, despite the toll the long hours had taken on his body, that his senses were still acute enough for the work. He understood the importance of making it known if he felt too fatigued; the geller field was all that kept the ship and everyone aboard from suffering horrific deaths. But at the same time, he knew he would be punished if he was suspected of shirking his tasks. So he pushed on, and it was no bother, really. He could handle it, he was sure. The problem was that if he really was as awake and functional as he wanted his crewboss to believe he was, then he hadn’t imagined that flicker on the field integrity cogitator. That could mean only one of three things. First, he had imagined it, and the fatigue was getting to him; he needed to take his lashes and be relieved to rest. Second, that there was a problem with the cogitator. Fixing that would only be possible to one of the attendant tech adepts, certainly not him, and he sought one out now, fervently praying to the God-Emperor that this was the case. For the third possibility was that there had, in fact, been a flicker in the geller field integrity. In which case, they might all be doomed already.
Spotting an engineseer monitoring another cogitator, Hardin hurried toward him. A few steps away, though, there was a mechanical groan from beneath the deck grating, a pop and a rush of stale air and dust blasted Hardin in the face. For a nearly a minute he was reduced to teary-eyed, doubled-over coughing. When he straightened up, the enginseer had approached and was berating him in choppy mixture of low gothic and bursts of static, and mechano-tendril pushed him aside to get at the grating. Hardin shook his slightly swimming head, and blinked, furrowing his brow. He had been doing something important. But now he couldn’t remember what. Begrudgingly, he concluded that fatigue was getting the better of him, and he reported to his crewboss for relief.
Finding a comfortable position with the growing bruises from the ensuing beating proved difficult, but eventually he settled in his slot bunk and let weariness claim him. As he took his first sleeping sighs, a thin cloud of fine white dust-like motes issued from his nostril and dissipated through the room.