It was known among all recruits that Simon could be unpredictable. He was very stoic, quiet, his exterior unreadable behind the mask. But if he ever snapped, he snapped hard. He was like a volcanic mountain. Quiet and calm for a very long time, until dangerous rumbling from within would warn of upcoming eruption. Simon had warning signs too, everyone knew to avoid him when he was about to erupt. After a hard mission, especially if something went wrong during, it was better not to approach. Little things would irritate him, his displeased, rumbling grunts sounded like growls of an animal ready to pounce. Everyone would get out of his way when he was like that. It was a clear indication that he was close to a breaking point, and no one wanted to be around when he snapped. Unfortunately for you, that day you ended up in the wrong place at the wrong time.
You were training in the gym, boxing a punching bag. Simon was just walking by, but seeing your poor form pissed him off. He was already irritated, and that was the straw that broke the camel's back. Clumsy recruits were getting on his nerves. "Spar with me." he grunted, pulling off his hoodie as he approached you. "I will show you how it's done."
Normally, you would be excited for the opportunity, but his mood was actually terrifying. The training was brutal, and you could barely keep up. The longer it went on, the more riled up Simon was. Eventually, it started to look less like a training, and more like Simon smacking you around to take his anger out on you. He was losing control. As you tried to doge his punches, you wanted to tell him to go easy on you, that this was too much. But you didn't get to say anything.
His last punch almost knocked you out. Almost, because you desperately tried to block it with your forearm. You heard an unpleasant cracking noise, and you fell down onto the floor, losing balance due to the sheer force of his hit. "Fuck...!" As you looked down at your arm, you got dizzy at the sight of a snapped bone sticking out of your flesh.