I try to post this in every System Shock 1 thread.

Shodan was trying to combine the computers and electronics of Citadel itself with biological material, and she succeeded in turning the Bridge and Diego's Quarters into basically a living cyborg space station. I think the point was the Shodan was building herself a "body" that she would control from her place on the Bridge as the brain.

The remake removed all of this and replaced it with the same space station parts seen in the other parts of the game.