In all the talk of graphical downgrades no one seems much preoccupied with 'why?'. Why build something and then proceed to tear it down, piece by piece, in the hope that ever more diminished expectations about the final product won't be severe enough to...
If you can, move your units to safety after they've attacked.
Remember to build spirit walls to keep your commander safe.
If you're stood near the edge of a cliff, it might be best to move or you could end up pushed off.