itch.io

 The codes appear to be hard-coded and don't change from what I've seen. so if you are save scumming anyway:
save the game
go hire the 4 mercenaries with the techie trait (Aike Hayashi, Dexter Colt, Doyle Bekker, and Samuel Spartan)
make them your followers
go hack the door and write down the number
restore the game
go to the door and use the number you wrote down.

You need to talk to the the slavers in the bar to move the story forward.  Depending on how you go, more with Charlotte can be available.

Very minor, and maybe it just hasn't been written yet but one of the slaves has a blank background for the third page.