Shove Voles pathing out of rooms

The general pathing of shove voles through a wall is horizontally or vertically. This is convenient, because it allows us to create ranches without using refined materials for the corner tiles.

However there is a simple trick for the shove vole to get out of the ranch anyway.

If he (or she) manages to excrement a new tile diagonally linked to an unrefined tile (see screenshot), he is able to pass diagonally through these tiles and escape.

This doesnt necessarily have to be a bug, but it is kind of surprising if every once in a while a tile-dropping shove vole gets loose in your base.