If I understand the basic normal rules you can go either direction in the dungeon. There is an optional rule called "Fleeing the dungeon". I do not see any benefit to this optional rule. It does not state that when fleeing you no longer encounter spaces. So what change is there in declaring your fleeing, besides the fact you can't go ahead? If that's the case, then just play normal rules and change direction.
In another forum elsewhere someone stated you still encounter the space. I searched these forums and found no answer.