On patrol during his third tour in April, Mills put his bag down on an improvised explosive device, which tore through the decorated high school athlete's muscular 6-foot-3 frame. Within 20 seconds of the IED explosion, a fast-working medic affixed tourniquets to all four of Mills' limbs to ensure he wouldn't bleed to death.
"I was yelling at him to get away from me," Mills remembers. "I told him to leave me alone and go help my guys.
"And he told me: `With all due respect, Sgt. Mills, shut up. Let me do my job."'
The medic was able to save Mills' life but not his limbs. Today, the 25-year-old Mills is a quadruple amputee, one of only five servicemen from any military branch to have survived such an injury during the wars in Iraq and Afghanistan, said Maria Tolleson, a spokeswoman at U.S. Army Medical Command. And instead of serving alongside his unit, he has been spending his days based at Walter Reed Medical Center, working on rehabilitation after the accident that dramatically altered the trajectory of his life.
Mills doesn't dwell on that. Sitting in his hospital bed, he describes his situation plainly: "I just had a bad day at work."
His family - especially his wife, Kelsey - admires him for that.
"I think he's Superman. I really do," she said. "It's amazing to see just how lucky he is. I mean, he's the luckiest unlucky guy."
Mills' recovery is expected to last at least a year. Already, there have been victories: A procedure performed at Walter Reed National Military Medical Center alleviated the excruciating phantom limb pains Mills was experiencing in the first weeks he was stateside.
He approaches each therapy session methodically, practically.
"There's no reason to sit here and look out the window and feel sorry for myself," Mills told The Associated Press in a telephone interview from Walter Reed. "It happened. I can't change the fact that it happened. I can't turn back time."
At Walter Reed, Mills is doing exercises designed to make his body leaner while strengthening his core, hip flexors, pectorals and shoulders. He bounces on a trampoline, trying to execute 90-degree turns with his torso. "There's nothing I really don't like (about PT), except I can't do two-a-days yet," Mills jokes.
While he's in the midst of getting his permanent prosthetics, Mills currently needs assistance to do things that most people take for granted, such as cooking and cleaning, or walking and running. As often as Walter Reed doctors let him, Mills makes his way to the Military Advanced Training Center to strengthen his body and prepare for long-term prosthetics. He currently has all four beginner prosthetics.
"They push you to your limit, then they push you a little more," said Mills, a high school football, basketball and baseball star who is more accustomed to bench-pressing and squatting to get bigger.
While he works at learning to use his new artificial limbs, Mills has an army of supporters behind him. On the Facebook page, nearly 20,000 people are tracking his progress and cheering him on virtually through messages.
The page serves as a window into his recovery, and his supporters watch eagerly as he surpasses milestones. When he began to walk on his prosthetics for the first time, a camera followed him as he nudged forward on a small track. With red and white sneakers laced on his prosthetic legs, and crutches gripping his artificial hands, he methodically takes one step at a time while tethered with a harness to the ceiling.
He doesn't just take a few steps. He walks the whole track.
"This is your first day?" an incredulous voice says from nearby.
"Yes, yes it is," he responds proudly, taking another step.
A short time later, another video showed more progress: He walks faster now, swifter than his first deliberate gait.
Videos also show him learning to roll and come to a sitting position in his bed, and learning, patiently, to use an artificial hand. One clip shows him removing colorful clamps from a bar and dropping them in a bucket. Another shows him using that same hand to feed baby food to his infant daughter, Chloe.
"Turkey and rice, tastes so nice!" he sings, as the baby girl opens wide and flaps her hands.
Only a half-year older than his injuries, Chloe has been a significant source of inspiration to Mills. He was there when she was born on the base at Fort Bragg, N.C. He left 4 months later for Afghanistan. Now, she sees him every day - sometimes helping him with his recovery.
Some videos show Mills doing crunches on his bed with an elated Chloe on his torso. In another video, he straps her into his wheelchair and zips around as she waves her hands in excitement.
Mills repeatedly talks of how "blessed" he is to be alive.
"Now I can watch my little girl grow up and see my wife and family again, and everything's good to go," he said. "I didn't die, so that's good. You've got to look at the positive things."
Mills' prognosis moving forward isn't clear, but there have been advances in working with patients who suffer similar injuries. Dr. Karen Pechman, who runs the amputee rehabilitation program at Burke Rehabilitation Hospital in White Plains, N.Y., said "only in the past few decades has the medical care existed that enables" people who incur the trauma or disease states that would result in quadruple amputees to survive, so it's not yet known whether those who lose all their limbs have their life expectancy diminished.
"There is nothing inherent medically about amputation that would affect subsequent health," Pechman said. "It is ... the activity level achieved by the patient that may impact on subsequent health."
As he recovers, Mills' story is compelling thousands to take notice and offer support. Recognizing that the family will face costs not covered by the Army and insurance, a fund has been set up for his family. There have been 5K runs held in his honor. T-shirts printed. Concerts, golf tournaments, motorcycle rides. Under the banner of hundreds who call themselves "Team Mills," fundraisers have been held in Kelsey's home state of Texas, in North Carolina where the couple lived and many places in between.
Nowhere has more been done, though, than in Michigan, where a recent spaghetti dinner at an American Legion post netted tens of thousands in donations. In Mills' hometown of Vassar, it's hard to find a tree, lamppost or telephone pole without a yellow or red, white and blue ribbon attached. Businesses throughout the 2,700-resident town feature signs encouraging prayer for the Mills family.
"I wouldn't want to go through it. I don't know anybody that would," said Paul Wojno, the principal at Vassar High School and the father of one of Mills' best childhood friends. "But ... if I had to pick one kid in this school that has recently graduated, I'd say Travis would be the one to try to do it."
Mills recently achieved his goal of progressing to the point that doctors OKed his move to a nearby outpatient facility that allows him to live with Kelsey and Chloe. Now, he's setting his sights on September, when his unit returns to Fort Bragg.
"I'll be there, hopefully on my prosthetics, and I'll be standing in my uniform and I'll have an arm on my right and left side and I'll be able to salute them as they come in. And I'll be standing there waiting for them," he said.
As for all of the supporters who call him a hero?
"Just because stuff happened to me, I don't think it makes me a hero," he said. "I think it just makes me a guy that did his job, knew the consequences of what could happen and something happened."