Nobody is brave *all* the time...not even the greatest heroes. In fact, to keep heroes human and make their stories compelling, it's necessary for them to experience some fear and, occasionally, not feel capable of facing up to it.
Can you think of examples in wuxia wherein the hero (not villains) chickens out? I'm not talking about cases in which the hero is clearly overmatched/overwhelmed and not fleeing would be foolish, but cases wherein the hero has a fighting chance, but somehow loses his nerve and chooses to run rather than fight.