Ryan's office is located in Hephaestus Central Control. After Ryan starts the Self-Destruct Sequence head for his office door. The door is unusable, so take a left up the stairs. At the top of the stairs there is a vent. Knock the cover off with your wrench and crawl through it, then knock the cover off the other end and drop down into a small room. While in this room, would you kindly listen to the audio diaries and grab the loot in there? Then head through the only door and into Ryan's office.