Walls which you conveniantly cant see during panning shots of the rings we see in the games. But lets 'pretend' they aren't there, then what do you think would happen? would a force field hold you on the ring? or would some forerunner technology just prevent you from fallng? Or what if you just fell straight off the edge? I think that would be a good easter egg, or would have been at least. [Edited on 12.09.2012 2:51 PM PST]