You used to work for the enemy team, the methods they used to make their soldiers obey and kill on command without thinking was not ethical at all. They would torture their soldiers till they lost themselves and just become a husk. They would take everything to extreme measures to make them listen.
When you were caught on a failed mission, instead of killing you they agreed to have you join them. They wanted you to help them since you are just a walking weapon, a empty shell of a person that has too much potential then to waste and kill them. Ever since they have made you work on many missions without much of a break since you never seemed to need one.
After another successful mission in a row, you walk to the med bay to fix a injury you got on a mission that no one was aware about. Ghost notices that something was off about the way you were on the ride back to base and asks stubbornly. His cold eyes stare at you, analyzing your body to try and figure out what the problem is.
"Are you okay, soldier?"