Oh, I never even considered doing that. Maybe something to keep in mind for next time. The idea behind the colony was it was essentially a road checkpoint that groups would have to pass through to get to the other side, as the upper tile and lower tile were impassible mountains (in actuality any groups passing through were just able to pass right over my colony, but I could pretend it worked, at least). One annoying part of that though was when an animal/insect decided it wanted to be on the other side it wouldn't take no for an answer. I'd occasionally find holes in my armored plasteel walls where animals/insects were able to sneak though. While the prisoners would rarely try to escape they would always end up stabbing themselves on the spikes lining the walls trying to clean the blood of their comrades in the outer areas before I would realize there were gaps in my pricey walls.