That wouldn't be considered "canon", as it is a hidden area that you can only access through noclip. Further more, it is required for him to be there for him to be on those staticy monitors.
You burst in on Gman while he was relaxing and checking out his favourite Guiness book of records!
I reckon he shows up, makes sure things are going to plan, makes some mysterious adjustments and manipulations if they aren't, executes a stylish G-peep, and moves on.