Expanding on what differs IPCs from Humans
Different from Humans, the IPC is a machine designed to operate on a basis of input and output, cause and effect, without the random variable of human behaviour. That means while a Human is influenced by biases, instinct, and emotions in making in its decisions, the IPC will simply take in the information it's presented with, and react to it accordingly, this means that IPC behaviour is repeatable and will never be random, if you present the same input to the IPC, it will always give you the same output, the IPC will never behave in an odd or aberrant manner like Humans might.
With self-preservation as it's top priority, the IPC will never behave in a way that will result in its certain death like a Human might do, while a Human security officer might, for example, sacrifice himself by jumping in front of a bomb to save the lives of his friends, the IPC will never do that, as that would surely result in its death. This, however, does not mean that it will never help people, while the IPC will surely save its colleague from gunfire, it will never act in a reckless manner and run towards gunfire to be a distraction.
While IPCs are designed to mimic Human behaviour due to its design, it will never fully manage to do this, with degrees of success varying by the model, and even it's emotional processes will operate on its binary model. Many mannerisms and social cues are lost to IPCs, and often even IPCs designed for service occupations will sometimes have problems interacting with Humans.
Also different from Humans, IPCs are purpose-made, and while over time they may learn traits or hobbies, only very rarely you will see an IPC switch its occupation.
Expanding on character's backstory
HHPU-1281, after being manufactured, was assigned to Mars for a year of mining as it's first posting and despite its shortcomings in socialization, 1281 attempted to talk with its coworkers during its downtime. This led to it developing a strong Martian accent and having a positive opinion about it's fellow human and unathi coworkers. 81 was the subject of constant pranks on the worksite and has developed a sense of humour some might call interesting.
Two weeks before its assignment was complete, 81 and a drill technician were injured when a mining charge malfunctioned in front of them, 81 was heavily damaged, and the technician knocked out. While 81 did manage to rescue itself and its colleague, the blast caused severe damage to its chassis. Hephaestus decided that repairing the chassis was simply not worth it and just decided to sell 81 at an auction. NanoTrasen saw a profit in acquiring a highly specialized mining unit, even while it was damaged, and ended up purchasing 81. Now repaired, 81 must adapt to its change of owner and new working environment in the NSS Aurora.