ironman have little problem- when you leave town or another settelment, game autosave,it take some time but game don’t paused… so enemy catch you.
In your personal situation i can recomend you try to run away from battle by move ALL your brothers to the end of tactical map( gex with white flag and press retreat button then) – so you will be able to retreat from the battle without getting injured and after that on the strategic map the enemies will somehow stand without moving, you can run away from them for some distance.
