Hey Mr. Jeff Wise, I really appreciated this post - I'm a Marine Corps. Officer Candidate and I know I'm going to need to grapple with my own fear in training and in real combat situations in the next few years. The SERE reference was especially helpful (updated link below)! Two things:

First, yesterday I was reading about the debate of having female soldiers as front line combatants. I read that men in combat who see women wounded or killed reportedly become uncontrollable. Do you know or have you read anything about this? Do men's brains dump a cocktail of hormones into their body when they see a woman killed? Do women's brains do the same if they see a man killed?

Second, here is an updated link to the SERE study:

Behavioral predictors of acute stress symptoms during intense military training
"In univariate and multivariate models, perceived stress, passive coping, and emotion-focused coping during daily living predicted acute stress symptoms in response to realistic survival training, whereas active coping and problem-focused coping did not."
http://www3.interscience.wiley.com/journal/122409995/abstract