How do I access the security office?

Walk around the deck until you see a door labeled security.

The waiting room was easy to access, but what about the office doors?

They're sealed shut. Maybe ask Warren to finally help?

Well, worth a try. Check on the doors again. They're now slightly ajar.

You can't prise them open with your hands. Maybe a suitable tool has been left lying around?

Have you revisited the corridor? There was a crewperson mopping the floors. And mops, you surely know by now, are notoriously versatile.

Take the cyber mop from the corridor and use it on the security office doors.