These walls had some controversy attached to them. They're too straight to meet up with others, as walls that intersect are typically interlocked. The kiva would have to be filled in if the wall extended out further (a room on the backside of these walls extends over a filled in kiva). You can also see a doorway/window (see photo 18) which would imply there should have been a room, or at least storage. Maybe it was just a practice wall to ensure the person building was up to par.