The year is 2367, man has finally developed the technology to allow for manned deep-space expeditions. There were several impediments to the final approval of the program, the largest being the guarantee that all personnel could make it back to Earth safely.
Thus, the PAC system was developed - the Personal Automatic Cryo-stasis System. In the event that any explorer were put into peril, the system (engineered into their suits), would put them into a cryogenic state, hopefully long enough that the crew could make it back to Earth safely while the ship piloted itself or was controlled by Mission Control on Earth. It would also comandeer control of the explorer's suit and attempt to keep the body safe by any means necessary.
The World President signed the necessary paperwork and a few months later, the team of astronauts was assembled - their lives dedicated to the success of the mission. Five brave men were selected from the academy, which was designed to teach the students all about the technology involved in the current design of star ships, as well as weed out the unstable or unfit.
The system was flawed, however, and some people slipped through the cracks...
The launch was successful and the crew was well on their way to the nearest star - Alpha Centauri. They made it out of the solar system without incident, slowly settling into their routine of checking instruments and data, conducting experiments and life aboard the star ship was easy after a time.
Then, as they coasted along towards their destination, disaster struck. Something collided with the ship - too small to be detected and too fast to be evaded. Some tech was knocked out - comms as spotty and some of the life sustaining tech was out of commission. The team assembled and attempted to make do with what was available on board. They tried as hard as they could, but the systems just could not be repaired. And so, despair set in among the crew.
They continued on their journey but the feeling of normalcy was shattered. Over time, they became more argumentative, more irritable. One resorted to compusively completing experiments. Another sulked about, avoiding all contact. The third would just talk to himself - or to a new friend. The fourth would simply be antagonistic and then resorted to passive aggression. The final astronaut resorted to chomping pills.
One fateful day, all hell broke loose aboard the ship - there was another collision. The previous accident had knocked the ship off course and into the path of this wandering comet. The ship remained intact, but too much tech was lost and the crew, already on pins and needles, could not handle it. They all flipped their collective shit.
One died during the impact - his head crashed into the microscope he was observing, through his eye and into his brain. One was smashed into the wall and finally went completely crazy, biting his own tongue in his insane state. Another talked to his friend and decided that hte only way out was to take his life - he sliced his throat with a scalpel from the med-kit.
The last two alive looked at each other across the table sullenly. The aggressive one jumped across the table at the final explorer who ran through the corridors of the star ship, seeking escape. He went down a tunnel and finally shut the hatch on thet hand of his aggressor. He was alone in the deep confines of the star ship. The aggressor eventually bled out.
But the story does not end there. The PAC system had activated on each of the astronauts, but it was too late to save them. Instead of saving their lives, the system simply attempted to keep the bodies in tact.
The lone astronaut fell into despair and quickly became addicted to the pills he was taking. Eventually, he ran out and had to venture from his hiding hole to get more just to stay sane. What he found horrified him - the dead bodies of his companions were being dragged around by the PAC system.
Thus, he found himself chasing after pills through the tight corridors and tunnels of the star ship, blinded by his insanity induced delirium, chased by the bodies of his dead friends.
The ship never returned to Earth.