Can I just say that you captured the male military mind set perfectly? In fact, I have to admit, you captured the female military mindset. Sex is a great stress release, and you would be surprised at how many people consider a portapotty an exceptable trysting place.
But one thing that I think you have also captured, espcially near the end: casual sex, in a lot of cases, ends up turning into a lot more. Military people have deep emotions, whether it be rage, happiness, love or hate. Casual doesn't last long, and friendships run deeper than any ocean. Can't wait to see what happens next.