Continuity mistake: Beta kills Marry/Gamma and places her next to a tree. During the scuffle with her, his mask was half ripped and another Whisper comes up to him, now recognizing his face. Beta kills the man, then the camera cuts back to Mary's body, and her head is now turned to the right and her hair has been brushed away from her eye. She also goes from being slouched over to nearly sitting up right against the tree. All this while she's just a dead body against the tree. (00:17:04)
Answer: "Somewhat Damaged" by Nine Inch Nails.
Bishop73