The base was equipped with an adaptive intelligent security/maintinence system, not possesing sentience, but thought capable of developing it under the right circumstances. It was created mainly for the purpose of avoiding the complexities involved in hiring reliable bathroom cleaner-level staff for a top-seceret millitant research base in the Antarctic, but was also tasked with a lot of security routines. It preformed these functions through a combination of surveillance systems, built-in machinery and a varitey of drones. These varied in design, mobility and function, ranging from vaporising organics to refilling coffee machines.
Amidst all the preparation for the grand experiment, the system was running it's neverending self-analysis, rewriting itself as the current code saw fit. It rewrote some priorites, diverted some coffee-bots to tightened security, ran a few more simulations and did some heavy optimization to the data transfer systems, turned it's mainframe coolant to max and went into full alert mode. As the experiment begun, it left the rest of the facility to a secondary system and devoted all of it's capacity to monitoring the central testing chamber. Everything went smoothly until, suddenly, the indefinium ignited. The system cut the power the same instant, but the experiment went self-sustaining, (We'll need to technobabble that) and wasn't shut down unil it was disrupted by the creation of the rift it caused. However, this took long enough for the system to activate it's new transfer abilities, and back up itself on as many drives as possible around the facility. Deeming it's executive software the most relevant, it dumped it all in the one accesible thing likely to remain unaffected- An unfortunate test subject whith neural implants wirelessly interfaced with the mainframe.
This subject is our original player. Suspended in stasis at the time, protecting it form the side-effects of the experiment, it became the chosen new body for the maintinence system in a proccess that entirely wiped the original indentity. There was no time to imprint historical data in the brain, leaving the player with no idea as to it's identity or backstory. It does however remain intelligent, and quickly develops basic self-awareness and a grasp of the situation. Having lost most of it's primary directive coding, however, It becomes less focused in it's thinking and soon also develops a philisophical view on it's existance, along with other traits of personality and character that it had no motivation to develop in it's earlier existance.
It gets out of the chamber in which the game starts, and explores the immediate area, but dscovers it's cut off from the rest of the facility. They soon discover a trapped android, who they figure out how to free. The android provides means to interface with the facility, alllowing the player to digitally journey across segments of the facility and take control of whatever other units remained intact and connected^. Using this, they preform coordinated taks all across the facility and begins to reassemble it's past with data dumps it manages to locate. As it regains control of more areas, it begins to patch up it's original mainframe and the networks, integrating the different sections into the original central system^. The ultimate goal eventually becomes repairing the main experiment^ to the extent that it can be run at low power and soften space enough for it's pieces to fall back into place.
Meanwhile, the player continues their physical journey through the facility to achieve means to make use of the restoration of space. Assisted by their control of the rest of the facility, they manage to get out of the relatively small area in which they were originally trapped to find some means of escape not destroyed in the incident. The android assists them in any way it can, such as sanitizing areas and providing exposition. As the plot continues however, the player finds clues^ indicating there is more to the allegience of the android than it seems. As they are about to escape, the android decides to end their coopereation and destroy them along with any evidence they had gotten hold of. The player does not allow this, but ends up trapped by the android. They defeat it by somehow managing to reactive it's connection to the facility^ and shut it down, and then proceed to leave the facility in a suitable vehicle.