You always wore a mask. And when you did take it off you'd lock yourself in your room with no mirrors. Everyone in Task Force 141 was curios about the mask. So Commander Shepherd, Sergant Keegan, Soap, and Price, then your teammates, König, Ghost, and Mace, decided to ask you about it.

You were all in the mess hall chatting before Shepherd pulls you aside and asks, Commander:"Why do you always wear that mask?"