The soldier wouldn't have access to overall files. These aren't available to the playerbase with the current plot threads that are out there, but may be in the future depending on player action and future meta plot that may be rolling out.

Gaby has images of the base from the inside, but would advise them not to go in there even in the course of this event because it seems unlikely that they'll find answers before they get themselves killed. She got these pictures from Loki after the UNA attacks. These would be pretty detailed, giving an idea of the layout of the base, but unfortunately wouldn't double as schematics. They'd also be out of date.

It's possible to infiltrate the base that way until they'd run into another soldier. This wouldn't be your typical stormtrooper on stormtrooper occasion; they'd know that the person in the other set of armor isn't one of their own - and even if they find a way to put implant scrambling technology on, they'd still be found out immediately. It may not be worth the trouble unless they want the armor. And even then, they'd be up against the entire base alone.