Chang Hwan Oh was not good at yelling at people. He’s soft-spoken with a calm demeanor. But when he was selected as a drill instructor for the Republic of Korea Army, he didn’t have much of a choice.

“I couldn’t yell at people, but in the army I had to. That was something I’d never done, but later I got used to it,” Oh said.

Oh is a 22-year-old second-year student at Syracuse University. Between his freshman and sophomore years he spent 21 months in charge of recruits at a training battalion in Daegu, South Korea. His service fulfilled the military requirement Korean men must complete between the ages of 18 and 35, Oh said.

Mandatory service in the ROK Army, which is the army of South Korea, is due to the continued tension between North and South Korea, Oh said. The tension is at its peak near the Korean Demilitarized Zone, a strip of land around the 38th parallel north that separates the two countries and acts as a military boundary.

Oh, who was selected to be a drill instructor for the training battalion only six weeks after he completed basic training at boot camp, did not have any interactions with North Koreans during his military service. His job at the battalion, located in his hometown of Daegu, was more involved with yelling at recruits and forcing them to run, he said.

The service requirement has faced backlash. In 2013, sons of 16 high-ranking South Korean government officials abandoned their nationality in favor of U.S. or Canadian citizenships in order to avoid their military duty, according to Yonhap News Agency, South Korea’s largest news agency. Although there are legal exemptions to the military requirement, it may be difficult to qualify for these exemptions, and those who do qualify may be shamed for not serving.

For Oh, joining the army after his freshman year of college was a personal decision, not a legal one. After his grandfather passed away during Oh’s freshman year at SU, Oh decided he’d join the army sooner than later, and chose to go the following year, rather than after graduating from college.

“Some people might say they lost their prime time during their young age, but when I think of how our grandparents were (in the Korean War), they vowed to keep their country. And we should appreciate it for them,” he added.

Oh said his experience as a drill instructor instilled discipline, maturity and the ability to lead in him. He also realized, he said, that time in college is precious and that deciding to do his military service after his freshman year put a part of his life on hold.

“I was actually thirsty for schoolwork during my years in the army. It was like pressing a pause button on my life while I was in the army, so now I’m back to my real life and ready to explore and ready to do my work,” Oh said. “I want to find myself back in real life.”

Part of going back to real life for Oh is getting used to the English language again, since he didn’t get to use English during his two years in the ROK Army.

Oh began to seriously learn English when he moved in with a host family in Easton, Pennsylvania at the age of 16. The move was a result of Oh telling his parents he wanted a career as a sports agent — his dream job is as an agent who acts as a bridge to bring Asian athletes to the U.S., and vice versa. His parents agreed, but only if he would start studying in the U.S.

Oh is still adjusting to academics and life back at SU, he said.

“There’s a phrase, the post military effect, for the Korean exchange students in this stage who are done with their military duty,” Oh said. “They feel delayed over others. They really work hard. They lost their two years in the college life. They really study hard, work hard, to catch up.”

Oh is dealing with the post military effect by surrounding himself with other SU students who have also done their service in the ROK Army.

“It does help because we have a common interest,” he said. “We play basketball together, we work out together. We encourage each other.”