If a stone wiggles in the wall you are building it is trying to tell you something. Stones have so few ways of communicating to us. It's not their fault.
I suspect if we were more developed we would have a much better sense of what was going on in their mysterious mineral world. While we may notice if a stone rocks or not, there is very little else we will are able to learn about their deeper workings. We are basically ignorant of any higher purpose or significance, except in the dull realization that they look good, and seem to like being made into various well-proportioned finely-crafted stone buildings and yes, placed in well-stacked dry laid structures too.
A proper dry stone wall has various sized stones in it that are not cemented together. This does not mean they are at all supposed to be loose, jiggling around or easily moved just by leaning on them or putting other stones near to them. They should in fact be 'locked in' together. A 'rock' that is properly laid in a wall, is not supposed to.
The position and look of the 'hearting' in the middle of your wall should give the impression that all the stones have been there for hundreds of years - as if all the stones have naturally bedded along a flat stoney pathway over time. They should look like they have found their most settled state. If a wall's innards look peaceful and none of the stones move, the stones are telling you they're happy and that the wall is going to last.