Simply put as the title suggest, can we have thralls that wander? Or maybe give a set path for patrol.
When we hold the activate button we could have a new option: patrol. Exactly as we would set to guard, we would have two (or more depending) placements sequences. The first placement is the start of the patrol, and the second would be the end (or if more sequences were allowed each placement would be a milestone with an [obviously] limit to milestones)