I heard people can't just walk all the way around the ring on the upper floors, and probably not the ground floor either
That actually wouldn't be entirely different from the buildings at Infinite Loop or even the HP buidings that were there previously. Both are/were traditional office buildings arranged in an oval like manner with a modest sized courtyard in the center. Those buildings appear to connect to each other, but you're probably better off just exiting the building and re-entering elsewhere much of the time.