From the obit:

In January 1966 he joined a battalion of US soldiers seeking to rout North Vietnamese snipers and was standing next to the battalion commander when the soldier paused to read a map.

"As the colonel peered at it I heard four loud shots as bullets tore through the map and into his chest, a few inches from my face," Arnett recalled during a talk to the American Library Association in 2013. "He sank to the ground at my feet."

He would begin the fallen soldier's obituary like this: "He was the son of a general, a West Pointer and a battalion commander. But Lt. Colonel George Eyster was to die like a rifleman. It may have been the colonel's leaves of rank on his collar, or the map he held in his hand, or just a wayward chance that the Viet Cong sniper chose Eyster from the five of us standing in that dusty jungle path."

And ...

At the AP's Saigon bureau in 1962, Arnett found himself surrounded by a formidable roster of journalists, including bureau chief Malcolm Browne and photo editor Horst Faas, who between them would win three Pulitzer prizes.

He credited Browne in particular with teaching him many of the survival tricks that would keep him alive in war zones over the next 40 years. Among them: never stand near a medic or radio operator because they're among the first the enemy will shoot at and, if you hear a gunshot coming from the other side, don't look around to see who fired it because the next one will likely hit you.