Yes, that's it! I think we only explored 5% of Zelan. On example of that is showed in this image of Zelan -> we have two floors but we never manage to go the floor on the bottom.
I remember seeing a couple of areas like that in Kuran too. Some of them don't seem accessible - there's no door or other way to get down there, it's just there. I think some of those areas just for looks and don't serve any function. You idea does make a lot of sense, though, so I like the idea of the elevators being directly connected like that.