He makes $15 an hour as a mechanic in the service department, but unless he's fixing a motorcycle, he isn't on the clock. Some days, like today, there isn't much to do, and he gets antsy just standing there. He needs the money and likes the work, in part because it keeps him distracted. His wife says he thinks too much.
"Just turning wrenches can be therapeutic," Mitchell says as he stands in his cubicle, wearing a work-issued shirt with "R.J." stitched on the lapel. "All it takes is being 2 percent smarter than the piece of metal you're working on."
It's an adjustment, this transition from being a wartime leader of men to a mechanic with the least seniority at Hacienda Harley-Davidson off state Route 101.
In combat, Mitchell, 27, was a genuine hero whose courage in Fallujah in November 2004 is credited with saving the lives of several fellow Marines. In July at Camp Pendleton, Calif., he became only the 11th Marine who fought in Iraq to win the Navy Cross, second only to the Medal of Honor.
Now, back in civilian life, he faces the challenge that confronts every man and woman who fights in a war: adapting to the rhythms of life outside the combat zone.
"It comes down to identity," said Michael Kilmer, who counsels combat veterans at the VA Medical Center in San Diego. "When you're a combat Marine and you leave the support of the military, it's like, 'Who am I now?'"
Two years after Mitchell left the Marine Corps, his transition, by his own admission, is still a work in progress. The sudden crackle of bubble wrap makes him twitch. He has trouble sleeping, and his dreams are often filled with violence. His wife says his war-related thoughts become especially vivid whenever he drinks hard liquor.
Sometimes, just for the rush, Mitchell and his best buddy - one of the Marines whose lives he saved - get on their motorcycles and open up the throttles, rocketing down the freeway at double the speed limit.
"They think they're invincible," his wife, Sara, proclaimed one recent night.
"Well," he told her, "we've proved that point a couple of times."
The Nov. 13, 2004, firefight in Fallujah that earned Mitchell his Navy Cross is now part of Marine Corp lore. A book, "My Men Are My Heroes," has been written about it. A photograph of the fight's aftermath - showing a bloodied 1st Sgt. Bradley Kasal, who also received the Navy Cross for his actions that day - has become one of the war's most memorable images.
Mitchell, a corporal and squad leader with Kilo Company, 3rd Battalion, 1st Marine Regiment, was on his second tour of Iraq. Until then, he had fired his M-16 only 15 times and wasn't sure he'd even shot anybody. Like many of his fellow Marines, Mitchell said, he "wanted to be the first kid on the block with a confirmed kill."
On the subject of killing the enemy, a platoon leader once told him, "The first one's a little rough, then after that it's like playing a video game, and you want to score as many points as you can."
The insurgents, however, were "very, very fierce fighters" and tough to take out, Mitchell found. Many were high on drugs. You could shoot them five, six times and they'd keep on running, hopping over a fence, vanishing down an alley.
Mitchell's platoon entered the city Nov. 9, 2004, and spent five days engaged in some of the fiercest house-to-house fighting of the war. On the first day, one of his good friends - Lance Cpl. Juan "Steve" Segura, 26, of Homestead, Fla. - was shot to death. On the fourth day, a sniper's bullet blasted a hole clear through Mitchell's right biceps. He got a medic to patch it up and kept fighting.
It was on the fifth day, inside a cinder-block hut later dubbed "The House of Hell," that Mitchell exhibited what his Navy Cross citation describes as "bold leadership, wise judgment, and complete dedication to duty."
He and three other Marines - among them Pfc. Alex Nicoll, Mitchell's best friend - charged into the house to rescue several wounded comrades. Almost immediately, an insurgent with an AK-47 opened fire from a second-floor staircase, ripping Nicoll's lower leg "like a saw cutting down a tree."
Instantly, Mitchell became a whirlwind of activity. Dodging grenades and the rapid-fire blast of automatic gunfire from above, he gave first aid to another wounded Marine, helped orchestrate a counterattack against the insurgents, then dodged another hail of bullets as he raced to Nicoll's side.
His friend was huddled in a small room, bleeding profusely, his leg all but separated from the rest of his body. Mitchell began wrapping a tourniquet around Nicoll's thigh.
It was at this point that Mitchell spotted a wounded insurgent reaching for a weapon. Mitchell's assault rifle had been shattered by a bullet, so he grabbed his combat knife and lunged - cutting the man's neck with a swift, decisive stab.
It was official: Mitchell had recorded his first kill.
Mitchell still keeps his hair in a military-style crop, and his right arm is covered with a large, colorful tattoo depicting a battle scene in Fallujah. The ring tone on his cell phone is a song titled "What If I Lost It" by the metal band Bloodsimple.
He's drinking a can of beer and standing in the kitchen of the Phoenix apartment where he lives with his wife, an oral-surgery technician, and their year-old son, R.J. III. On the kitchen counter is a plastic zip-lock bag where he keeps the various fragments of shrapnel that have been removed from his body.
One piece is from the bullet that pierced his arm. A second is from a mortar round.
"And then, this piece," he says, pointing at a third pellet, "I just pulled it out of my chin one day. I thought it was a zit."
He still has "constant ringing" in his ears, he says, a result of the automatic gunfire inside the House of Hell, which he describes as "the loudest noise you could ever hear."
There are also certain things he tends to avoid as a result of his combat experience. He prefers not to watch particularly violent war movies, especially a film like "Black Hawk Down," whose battle scenes he says are remarkably accurate.
Then there are his dreams, which always seem to be "combative in nature."
"I've talked to my dad and other vets, even older vets, Korean War vets, early Vietnam vets," he says. "They said it never completely goes away."
Mitchell left the Marine Corps in 2005 because he wanted a new challenge. He enrolled in the Motorcycle Mechanics Institute in Phoenix - "the Harvard of the motorcycle industry" - and took the Scottsdale repair job after graduating.
His combat experience has helped him in civilian life, he says. He's more disciplined. More driven to be successful. And, perhaps above all else, more confident. What his performance in Fallujah proved to him, he says, is that he had the courage to act with honor at the moment it mattered most: when he was forced to risk his life to do his job.
In other ways, his war experience has left him feeling slightly isolated. The average person, he realizes, simply can't fathom the hellish experience of surviving combat.
That's one of the reasons he remains so close to Nicoll, the Marine who lost his lower leg. For several months, Nicoll - who's also studying to become a motorcycle mechanic - even lived in the same Phoenix apartment as Mitchell and his family.
One day a few weeks ago, he and Nicoll were leaving a nearby bar, both of them "pretty annihilated," when a bouncer started pushing Nicoll out the door.
"I'm sorry, but you just don't do that to the guy I wrapped a tourniquet around," Mitchell says as he recounts the story.
After some pushing and shoving, the two ex-Marines and two bouncers ended up in a full-blown brawl. The next day, Mitchell returned to the bar because he couldn't remember exactly what happened the previous night. A bartender told him never to come back.
Despite his violent dreams, his violent memories, his occasional feelings of contempt for people who like to pontificate about Iraq even though they've never set foot in the country, Mitchell has little interest in therapy. He says he once sought counseling through the Department of Veterans Affairs, but it didn't do him much good.
"Every time I went, it was like, 'Well, we can give you these pills,'" he says. "I don't want to take anything that's going to take my edge off or change the way I act or feel."
He also doesn't like to discuss the details involved in killing a man by slitting his throat with a knife. He permits himself to say this much: "It's savage - it's a very, very savage act. If Alex (Nicoll) were here, he'd tell you that it is the most savage thing he's ever seen in his life."
Mitchell's parents, both retired railroad executives, think their son has made a remarkably smooth transition to civilian life. His mother, Martha Raiser, 57, who lives in Leon, Iowa, says he "hasn't skipped a beat" since he left the military. His father, Robert Mitchell, 63, who lives in Omaha, Neb., said R.J. is "more determined to do well than I've ever seen him."
Still, his father, a Vietnam veteran, says "only R.J. knows" how the war has affected him. He noted that his son calls him every year on the anniversary of the death of Lance Cpl. Segura, the friend who was killed on the first day of fighting in Fallujah.
"He just calls to tell me he misses him," the elder Mitchell said.
It's midmorning at the Harley-Davidson dealership, and Mitchell has decided to take one of the Harleys for a test drive. His flannel jacket bloats with air as he zooms through the neighborhood of strip malls and office parks.
He likes to go fast, especially when he's on his own time, on his own bike. He doesn't worry about speeding tickets. Most of the cops in Arizona are ex-military, he says, and he has a Marine sticker on his Harley.
"I've passed people that were going 100, 120, like they were standing still," he says.
He has few regrets about the events of the past three years. He doesn't regret leaving the military. He had "a really, really good run," he says, and "wanted to see what else I could have a good run at."
Perhaps his only regret, he says, is this: "I could have done without getting shot."
Then, after a pause, he changes his mind.
"Actually, no," he says. "Actually, I'm kind of proud of that."