…intent on some private transaction with the war

1

"You just don't know," she said. "You hide in this little fortress, behind wire and sandbags, and you don't know what it's all about. Sometimes I want to eat this place. Vietnam. I want to swallow the whole country—the dirt, the death—I just want to eat it and have it there inside me. That's how I feel. It's like … this appetite. I get scared sometimes—lots of times—but it's not bad. You know? I feel close to myself. When I'm out there at night, I feel close to my own body, I can feel my blood moving, my skin and my fingernails, everything, it's like I'm full of electricity and I'm glowing in the dark—I'm on fire almost—I'm burning away into nothing—but it doesn't matter because I know exactly who I am. You can't feel like that anywhere else." 

2

"What happened to her, Rat said, was what happened to all of them. You come over clean and you get dirty and then afterward it's never the same. A question of degree. Some make it intact, some don't make it at all. For Mary Anne Belle, it seemed, Vietnam had the effect of a powerful drug: that mix of unnamed terror and unnamed pleasure that comes as the needle slips in and you know you're risking something. The endorphins start to flow, and the adrenaline, and you hold your breath and creep quietly through the moonlit nightscapes; you become intimate with danger; you're in touch with the far side of yourself, as though it's another hemisphere, and you want to string it out and go wherever the trip takes you and be host to all the possibilities inside yourself. Not bad, she'd said. Vietnam made her glow in the dark. She wanted more, she wanted to penetrate deeper into the mystery of herself, and after a time the wanting became needing, which turned then to craving."

3

"... she took a greedy pleasure in night patrols. She was good at it; she had the moves. All camouflaged up, her face smooth and vacant, she seemed to flow like water through the dark, like oil, without sound or center. She went barefoot. She stopped carrying a weapon. There were times, apparently, when she took crazy, death-wish chances—things that even the Greenies balked at. It was as if she were taunting some wild creature out in the bush, or in her head, inviting it to show itself, a curious game of hide-and-go-seek that was played out in the dense terrain of a nightmare. She was lost inside herself . . . She had crossed to the other side. She was part of the land."

-Tim O'Brien. The Things They Carried. Chapter "Sweetheart of the Song Tra Bong".