Mitchell Sanders is obsessed with the truth. He's the one who's always trying to figure out what the moral is, whether it's of a story or a corpse lying in the road. He doesn't need the moral to make sense, or the story. He just needs there to be one. He's intelligent. He's the RTO, or Radio Telephone Operator, so he's all about communication.
He's the one who tells O'Brien that Bobby Jorgenson is a part of the group now, and that O'Brien no longer belongs. He's the one that O'Brien goes to first for help with his revenge plan, and he turns him down, calling O'Brien sick.
Outside of the platoon, Mitchell's kind of a ladies' man. Along with the rest of his gear, he carries condoms (which seems rather optimistic) and a set of starched fatigues for special occasions. (Like what, one wonders?)