The railgun is exposed directly to hard vacuum, so when Sitri cuts open its tiny bay, everything goes crazy. Pressure loss results in a gale-force evacuation of atmosphere, and alarms start blaring shipwide until there's too little air for sound. Even then, red emergency lights flash incessantly. Purson's virus may keep the damage control bots from going to work just yet, but the alarms aren't slaved to the computer; they have their own sensors for when the pressure gets too low too fast.
There's one last trick the virus has, with its claws deep in the guts of the security and damage control systems. Once Sitri pulls out the black box probe and sticks her own drone inside, both more than half as long as she is tall, the virus just needs her to send the signal and the railgun will open fire. Impart some momentary drift and spin on the ship via maneuvering thrusters, put the bulkhead plates (complete with radiation and magnetic shielding) back in place with some welding putty, and make sure the railgun is pointed at the second asteroid receding in the distance, and push the big red button.
The railgun fires off with a ship-rattling pulse, felt through the boots and up the body of Sitri's pressure suit. If the plotting algorithm was correct and Andrealphus's (legal name: Ngare Kimunya; born 2029 CE; currently a citizen-shareholder of the Phobos Megafactory) estimates of the railgun's power were accurate, then the drone should be impacting with the asteroid in a week or three, at which point it will unfold and begin cannibalizing all non-essential components to feed mass into its own printer, and start the mining process.
The whole process – from chance sighting of an asteroid that must be skipped (but now, thanks to observation, has a known path that may be plotted) to trusting they can hit that target with a high-tech slingshot – is risky and full of room for error, but the potential payoff is boundless.
Sitri and the rest of the Goetia incorporated together several years ago. Most had already undergone personal incorporation, trading their potential future wealth and reputations on the stock market in a practice begun once corporate persons started getting more legal rights and tax benefits than born humans. At the behest of Asmoday the Great King, Governor of 72 Legions (legal name: Yuan Li; born 2032 CE; no further information available, would you like to make another query?), they each sold a significant percentage of their personal stock to themselves as the board of directors of Goetia, Ltd.