How can you possibly build a tile in the same space as your face? I understand deconstructing something underneath you and falling or removing a roof tile and getting buried in sand, but building something in the space that I'm occupying? No way.
A dupe standing on level 1 building a row of tiles at the height of their head on level 3 will build the tile in the same space as their head, trapping them and leading to suffocation. Should the path-finding instruct the dupes not to build a tile in the same space they occupy or prevents them from pathing away?