From Hue 1968: A Turning Point of the American War in Vietnam, by Mark Bowden (Atlantic Monthly Press, 2017), Kindle Loc. 6136-6148:
Men learned firsthand how to gauge the severity and type of wounds. Shrapnel burned. It was hot metal. If you were hit by shrapnel it felt like someone touching you with fire. With a bullet the first thing you felt, after the shocking impact but before the pain, was wetness. Shrapnel cauterized the wound instantly, but bullets made you bleed. You tried not to think too hard about it. Thinking about it was tempting fate. And fear? Fear was just the air you breathed.
Most kept going. The sun would rise and they would form up and wait to be told to run across another street, climb through another wall, barge through another door, knowing each time it might be their turn to pay the price. Art Marcotte, a private from Boston, would feel sick to his stomach with fear when he was ordered to step out into a street or run across a courtyard under fire. But he went.
Hygiene was a memory. Since many had been plucked from the field and sent directly to Hue, they had not washed in weeks. At night they shared a toothbrush. All of the men gave off a pungent odor. One of Connelly’s jobs as corpsman was to find a safe spot to dig a latrine, a trench. He would find a chair and knock the seat out of it to serve as a commode. One day in his second week Fox Company passed through a wastewater treatment facility near the canal. It had large circular vats made of concrete divided into reeking pie-shaped segments where human waste settled out before the water was drained off for the next step in its purification. A rocket blast knocked three marines into one of them, and because they were loaded with gear, there was a danger they might drown. Connelly and another corpsman had to plunge in to pull them out. They hadn’t thought it possible for men to smell worse, but after that, they did.