AKA: A Room to Breathe
Player 14, Tonya (Alisa Marshall) is not a captive like the others. She is in fact, working in league with those running the "game."
After the other contestants are dead, Tonya deactivates her collar and walks out of the room with the Host. It turns out the "game" was some type of experiment on human nature and Tonya is placed in every trial of it in order to observe and experience it first hand, though it is unclear what the purpose for the experiment is.
After writing down some notes about the experiment she just endured, she disrobes and lets herself be placed in the next "game". One of the players wraps a blanket around her and asks if she is okay. Tonya hyperventilates, playing her part. She looks around at the new group, and when no can see her, smiles...
Thanks Tim (Spectre)!