That's what I'm thinking. I couldn't find a specific reference in faqs to the in-base "ceiling", or at least as far as it figured in here. I'd thought the only way to navigate between the planes-- above, base level, and below-- was via teleporters, but now it seems that "outside the base" does not heed these planes(?) So the only actual room I need is the entrance, and everything outside that room is a free for all? All that's really needed is a floor of some sort to stand on?
The only other thing I'm wondering about now is I read that I can "build above up to a height of 900 or a low of -2,000"-- but what do those numbers mean? What is the measurement of a fully open, high ceiling to low floor base room on that same scale, for reference?
Off to float floor tiles to FIND MY LIMITS