"It was the stupidest, most Southern-fried, lame-brained decision I ever made in my life to vote to let them go ... I actually cast a vote that I knew would sign our death warrant."
-- Marcus Luttrell, from "Lone Survivor"
Not a day goes by that newly retired Navy SEAL Marcus Luttrell does not think about the two goat herders he and three comrades encountered on a late June day in 2005 while searching Afghanistan's border with Pakistan for an elusive Taliban leader.
Stealth is the tradecraft of the elite special forces soldiers, and that element of surprise was compromised when the herders approached the unit, Luttrell said during an exclusive interview Tuesday on TODAY.
The team members had to make a quick decision: Kill the herders, or let them go and risk giving away their position to the Taliban.
The men of Seal Team 10 made the decision that comported to the rules of engagement, but it ended up costing the lives of Luttrell's best friend, two others and 16 more servicemen who tried to rescue them. They let the herders go.
Luttrell, who collaborated on a new book about his buddies' heroism and his own harrowing escape, told TODAY host Matt Lauer that he doesn't have "survivor's guilt" because he lost a lot on that mountain as well.
"I died on that mountain too, sir," Luttrell said. "I left a part of myself up there. I think about it every day. There's not a day that goes by ...."
He let the sentence hang there, as emotions swept over him. He remained composed and told the story.
‘A bad situation’
Seal Team 10 was searching for a Taliban leader who was holed up in an Afghan village near their position when they came across the goat herders and a flock of about 100 goats.
"We knew it was a bad situation. Anytime we get compromised, it's not part of our job," the Texas born and raised Luttrell said with a distinctive drawl. "We pulled them off to the side, sat them down, put security on top of them. Then one by one, we started talking to each other and decided what were going to do with them."
Executing the Afghanis would have been illegal, under U.S. law, and could have exposed the American soldiers to prosecution back at home. The alternative was to let them go, and risk tipping their hand to the enemy.
And that's exactly what happened.
Within a short period of time, the unit was surrounded. Taliban fighters encircled them, and had the advantage of numbers and higher ground. The unit was out-manned 80 or 100 to four.
"It was game on then. I took the first shot," Luttrell recalled.
The Taliban started picking off members of the unit quickly. Luttrell's best friend, Lt. Mike Murphy, basically sealed his fate when he ran out in the open to use a cell phone to summon a rescue team. He and two other unit members died that day, as did all 16 aboard a U.S. helicopter destroyed while trying to get to the men.
Luttrell crawled some seven miles to a village and begged villagers to help him. They agreed, and hid him from the Taliban by moving him from house to house, at the same time nursing his wounds.
"They weren't going to give me up," Luttrell said, explaining that there is an ancient custom in the region that villagers must aid people requesting sanctuary.
Eventually, Luttrell made out of the village and back to the U.S. He paused when Lauer asked him if he still regrets his vote to let the herders live.
"Every day. Every day," said Luttrell, who was awarded the Navy Cross for heroism last year. "It would be worth me doing the time in prison if my buddies were still alive, if that answers your question."
Luttrell's memoir, "Lone Survivor: An Eye Witness Account of Operation Redwing and the Lost Heroes of SEAL Team 10," was released to bookstores Tuesday, a day after he was discharged from the Navy. You can read an excerpt here.
© 2013 NBCNews.com Reprints