If after applying she moves, that would be considered as a change in status where PA has moved out of country. Other members can correct me on this, but this will mean that the PA would again have to show intent to return back to canada. If she is a student, then enrollment in classes; if she is working, then letter from the employer etc.
It is hard to stay away from the spouse, we all have and are going through this process. But if you want the application to be processed faster, my recommendation is for the PA to stay in Canada.