TALES FROM THE FRONT:

Editor’s Note: This is the fourth in a six-part series about war veterans who are members of UC Irvine’s Veterans Student Union.

Thomas Sim discusses his time as a Marine rather casually. Whether he is talking about harsh drill instructors, exploding mortars or his desire to prove himself in Iraq, he remains tongue-in-cheek about many things.

His shy smile often shows through in dry humor, his tone never wavers, and his peaceful exterior shields his emotions. He is polite, forward and educated.

So when he describes the mentality of the Marines, his tenor, or lack thereof, may offend some people.

“It’s a culture of killing,” said Sim, a lance corporal in the Marine Reserves. “Marines aren’t afraid to be honest about it — we kill people.”

Sim, 24, understands some people can be threatened by the mind-set. He says the concept is “taboo,” but he also believes the training is necessary for survival.

“It doesn’t seem weird to me anymore,” Sim said of his training before going to Iraq. “You can’t just fire rifles to desensitize you, make you calm.”

The Marines, which has a cult-like following according to Sim, immerses its young men in the mentality of killing.

Answer to roll call — “kill.”

Rallying cry — “kill.”

Celebratory chant — “kill.”

But despite its necessity, Sim said, the mentality doesn’t make the transition back home easy, especially for someone whose decision to join was anything but thought out.

A sophomore at a junior college in 2003, Sim was working at his school’s store when a Marine recruiter, in full uniform, walked in.

“He looked pretty sharp,” Sim said.

Interested in history and the concept of the citizen soldier in ancient Greece, he wanted to be a part of something bigger than himself. The Marines had the reputation of demanding the best, so he decided to join.

“It was kind of spur of the moment,” Sim said. “They asked me how long I had wanted to join — I said since last week.”

Sim’s mother supported his decision as he was old enough to make his own decisions. His sister, he recalls, was not pleased and wrote him constantly while he was away and when he came home. Now, Sim says, she is quite proud.

Sim was deployed to Iraq from March to October of 2005. The Marines mind-set pressured those who hadn’t been deployed to volunteer for duty, Sim said. He was eager to prove he was strong enough to defend his country and to call himself a Marine.

“It’s only after getting deployed you realize you don’t want to get deployed,” said Sim, whose job was to assemble, build, load and maintain explosives, among other tasks.

But his training had paid off. Stationed near Fallujah, his unit came under steady mortar fire and feared infiltration. But he kept his cool, focused on his job, and buried his emotions. If his fear got the best of him, it could result in getting himself or someone else killed.

“I was in a Zen-like state when mortars were falling,” he said. “I was kind of in denial. In dangerous situations you don’t have the luxury of vetting feelings.”

Sim was stale. The majority of his time in Iraq was filled with boredom, a barren landscape for which he felt nothing — a sharp contrast to the moments of destruction.

“If an hour is your time there, 55 minutes is pure boredom — five minutes is terror,” he said.

And when those five minutes came, while everything and everyone around him was falling — Sim stood.

Close to the end of his time in Iraq, he was on patrol when a chapel was destroyed. While pieces of the shattered building dusted the landscape and other Marines hugged the desert sand, Sim didn’t move.

“I recognized the sound,” Sim said. “I just kind of went about my business. In my head I was done with this.”

Not much later Sim came home, but he wasn’t sure what he was coming home to.

His girlfriend had broken up with him while he was deployed, and he no longer felt comfortable in Northridge. He wanted to go to school, but struggled to find motivation. He didn’t know what to do, but he knew he wanted something else.

“When you go to war, life stops; but people’s lives at home haven’t,” he said. “I felt like I was two years in the past when I came back.”

Sim said there is no real transitional mechanism for servicemen coming home, but he was encouraged by his sister to go to school. Sim found a place at UCI.

A political science major, Sim has two years left in the Marine Reserves and struggles with some of his issues about his time in Iraq — “the power of denial,” he calls it.

He may have outlasted the mortars, but there are times the anxiety crawls to the surface.

Small pressures or frustrations will leave him in a panic. He’ll sweat and shake, and the emotions he buried long ago find new life.

“You bury those feelings, but it finds a way to filter out,” he said. “It is still pretty hard. [Marine life] is still a part of our culture foreign to the civilian world.”

THOMAS SIM

Age: 24

Hometown: Northridge

Career Goal: foreign policy, state department, or working for the government

Voting For: Barack Obama

Most Common Misconception About Iraq: “That we’re the heroes. The heroes are the ones that don’t come back.”

DANIEL TEDFORD may be reached at (714) 966-4632 or at daniel.tedford@latimes.com.