The soldier from Bridgewater, N.J., took four bullets when an Army psychiatrist opened fire on the army base, killing 13 people and wounding dozens more. Carroll was among the witnesses who heard Major Nidal Malik Hasan yell "Allah Akbar" before opening fire on civilians and his fellow soldiers.
Carroll said he doesn't have nightmares about the shooting, but is still healing in mind, body and spirit.
"Every time I see someone from that kind of religion I'm always stopping and thinking 'I wonder if he's a terrorist?'" said Carroll of how he looks at Muslims now.
But he quickly added, "I don't go around and just like start hating on everybody, because we're all human beings."
In fact, he believes in the mission in Afghanistan, and -- despite his four bullet wounds -- insisted to the Army that he be sent there as originally ordered.
"I know that not all people there are bad. A lot of people there support them(the bad guys) but more people support us and what we're trying to do," Carroll said.
"It's just who he is, he's not a quitter," said his mother, Teresa Scholte.
And in fact, Carroll long ago had the words "Never Quit" tattooed onto his left forearm. It is a tattoo that is now just inches away from where one Malik's bullet entered his body. He has all but recovered from those wounds. Carroll said he only feels the wound to his upper thigh as a sort of tightening when he begins his daily runs.
Remembering back to those moments at the Soldier Readiness Center, Carroll said "I thought it was training at first. I got hit twice before I realized it was something real." He added, "I got hit twice before I realized it was something real."
Carroll tried to drag a wounded buddy out of the line of fire, and took another bullet for that effort. Then he realized he didn't even have the strength to get his comrade outside.
"I could've sworn I was in there an hour," he said. But they said the shooting only lasted 4 and a half, 5 minutes, I believe. It felt way longer."