I've told my dwarves to build a protective rock 'sheath' around my column of up/down stairs (thrust to the floor of a cavern) in the following pattern:
OOOO RXXO RXXO OROO
O = Wall build order R = Rock X = Stairs
But they've decided (in their wisdom) to leave the parts above cavern-ground-level as such:
OWWO RXXW RXXW ORWO
W = Wall
Since the walls are preventing my dwarves from completing the building, will they also stop bats and other horrors from getting in and scaring my dwarves away from my main (and only) staircase?
I know, I know, I should have put preventative measures in place before breaching the cavern, but it's my first time!