Down in the Rapax cellars you'll find the constable behind a locked door. Pick his pocket (or kill him) for the key to the safe in his office. That's where the other deposit slips are kept.
The computer on top of Gigas is only if you're single-aligned with the T'rang and want to destroy the Umpani ship in orbit around Dominus.
You will meet the Prince one more time, on Ascension Peak...and this time, he won't pop out
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