American and Afghan forces were briefing each other at a forward operating base on March 11, 2013, about that day's mission when machine gun rounds suddenly rained down on them.
The group immediately looked to see where the shots were coming from. The lone airman in the group, then-Tech. Sgt. Delorean Sheridan, identified the source of the shots, which turned out to be coming from a truck in the base's motor pool.
The shooter was a new member of the Afghan National Police who had slipped unnoticed to the bed of the truck and taken control of its machine gun.
It was a so-called "green-on-blue attack" — when supposed allies attack friendly forces. Meanwhile, insurgents from outside the base joined what was clearly a coordinated attack, sending more rounds into the grouped-up men. Bullet fragments even struck Sheridan's body armor.
Sheridan decided that Afghan National Police officer or not, anyone who fired on him from within hand grenade range was conducting a near ambush and it was time to respond with force. He sprinted 25 feet to the truck and fired at his attacker up close and personal.