My character has failed a Will Save. He's Frightened for 6 rounds. That means that he
flees from the source of its fear as best it can... [and] can use special abilities, including spells, to flee; indeed, the creature must use such means if they are the only way to escape.
Straightforward enough. I've got to run away. So, I double move away from the action on my turn. But the party is fighting in a complicated building with lots of rooms and corridors, and the rest of the party is engaged with, and obstructing my foes from pursuing me. Do I need to keep running, in any direction that's away (or even a random one, as one GM who I'm almost certain was wrong insisted) until the fear effect ends? Or If the object of my fear is out of sight, and I'm confident it can't reach or harm me, can I stay put? What if I ready an action to continue running as soon as the opponent comes into sight?
If I can't stop running... well, a 5 round fear is going to leave me very far away from the rest of the party.