Murph, in a really good comment-- the whole comment thread is helpful, so hie thee to it!-- asks if the decision/choice made in the dark moment is a "right or wrong" choice--
Well, right, wrong, I don't want to be judgmental. :) But for this person to resolve the internal issue (fear of whatever, lack of trust, etc), he/she probably needs to choose some course or action which forces the overcoming of that. If he can't trust, he chooses to trust. If she can't commit, she chooses to commit.
The clever part is... when this is exactly what's needed to give the power to resolve the external problem in the climax-- when trusting brings a new ally, say.
Let's think about possible dark moment choices that are "wrong" in the sense that they do violate some common morality. I'm thinking of the woman who is utterly dedicated to honesty, always tells the truth, no matter what the cost-- and then, in the dark moment, decides she had to lie to save someone or protect something important.
p.s. If you're new to this blog, please note that the comments on posts are often more interesting than the posts themselves. :) So if a post subject interests you, always check the comments! The commenters often provide great insight and sharp examples.