There Is A Reason

"Yes, because it was a mistake," Arthur said, meeting J's confused gaze. "While I was training in the army, I soon realized that it was not what I wanted. What I was chasing was my parent's dream, not mine." 

Arthur remained to look at J's confused face. "You might be wondering, why would I leave the armed forces to become a private security contractor when both have almost similar functions," Arthur said to see J nod her head. 

J knows the function of private security contractors or the private army is almost the same as the military or armed forces. They can protect, save, and convoy the VIPs or high-valued facilities and buildings. And sometimes, private armies serve as supplements or support to the military. But J always hears Jacob reminding the officials that they were just to defend and not to attack.