It can also work in the other direction. If you go so deep into the feeling, being 100% present to it, that there's no consciousness left to compare the pain to memories of non-pain, you can be in a world of pain, but not suffer. I did that while having a cavity filled without anesthesia, and during twice-weekly sessions of having electricity run through my leg to stimulate an atrophied muscle. Unlike distraction techniques, though, you can't do anything or respond to your surroundings, so I can see why it wouldn't work for someone in the military.