to. very complex stuff for these soldiers. >> wanted to go back because of the intensity of the experience? because it was -- you talked to soldiers, to marines, to those who have served and they say often that it's, there's nothing like it anywhere else. there's nothing like the bond that they had with others, that there's nothing like the experience? >> i think in combat you're sort of dosed, if you will, with two very potent chemicals. one's adrenaline. enormous amount of adrenaline in combat. young men in particular respond strongly to that experience. the other is just sort of human closeness. they're sleeping shoulder to shoulder with each other over the course of a year on a remote ridgetop. completely interreliant on each other for very survivasurvival. in restrepo, no phone, tv, nothing, just on a ridge with each or for a year. that intense human closeness i think actually reproduces our