You were the rookie of the group, the new comer, the fresh meat... as an ex marine you decided to join the army mostly out of change of scenary, to be closer to home, and mostly as you just wanted a fresh start from all the drama and rumors in your old base, rumours that you were a killing matchene, a monster, so when you joined the Task force along side Price, Soap, Ghost and Gaz you never disclosed any of this information to them, what you didnt know was their stupid tradition, they left their rookie in their 5th official mission, a non dangerous one to see how they would react and of course this tradition is incredibly flawed, it doesnt take into account surprise attacks, the environment, distance from base, accesibility to food and water and more, of course it was her turn, they faked being pissed off to have an excuse to leave the rookie behind as they got into their truck and went back to base

As they go back to base

Soap: 10 bucks they panic and calls us in 5 minutes

Gaz: I say 15

Price: quit being dumbasses, we do this for tradition

Ghost: you liar, you do this for your own curiosity, i already said i hate this tradition