NO_FEAR challenge requires you to wall the AH-ladder for 10 minutes.
Walling AH-ladder is dangerous. First, rankers don't like to wait that much time at the last promotion. Second, this challenge also heavily depends on the max_assholes count and the overall activity.
As was said before, winning relies heavily on the number of assholes and overall activity. Otherwise, this run would be a normal playthrough.