Regina

Regina was a soldier of a Red Team squadron. She, along with 6 other soldiers, was locked in a room with the doors only opening if the seven troopers in the room could reach an agreement. After a murder-mystery surrounding the mysterious death of Hutch is solved (every single person in the room shot him for different reasons, Regina's reason being because she hated Hutch for stealing her rations earlier), the Reds and Blues slaughter each other.

Trivia

 * She has Achromatopsia (the utter inability to see color), coincidentally just like everyone else in the room.