It will only return to old map if there is an old map to return to. And when you return to an old map, it removes the old map from the list of old maps. So if your pause screen is a map that you jump to, remembering where you were, and you "return" from the pause screen, then yes, it will just go back to the map you were playing on. But if you "return" from there, then it will quit (unless you had another map in the list before that). If you need to be able to quit from the pause screen, it should probably return to a specific location on the old map where there is a special function that returns to old map again, thus exiting the game. (I believe when you "return to old map" you are still allowed to specify a location). Another possibility is to try activating a series of functions that performs "return to old map" twice in a row.
