Because of a disk injury, he struggled through his first day of training, eventually using his firearm as a prop to help himself stand up from a prone position.

Unfortunately, the drill instructor caught sight of this infraction, and unleashed a torrent of harsh words. Moon Hee Jun eventually boiled over, yelling at the instructor when he pushed it a little too far!

"Because of my disk, regardless of what I want to do, my lower body sometimes loses strength," he said in an interview later. "I was about to apologize, but he was too harsh on me. I became too angry, and eventually..."

Watch the clip below.

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