At some point, the prisoner managed to escape captivity and made his way up a cliffside. The Diamond Dogs leader, Venom Snake, who was himself present trying to save another prisoner around this time, found him and proceeded to extract him.
Behind the scenes
The prisoner is a character in Mission 5: Over the Fence. Extracting him accomplishes the related mission task. When recruited, he is given the name of Spunky Sturgeon. If the player extracts him after rescuing the Soviet bionics engineer, Miller will express confusion as he's not the main target, before nonetheless accepting him.
- ^ Metal Gear Solid V: The Phantom Pain, Kojima Productions (2015).
Benedict "Kazuhira" Miller: It's a prisoner. You gonna extract him? We'll find out if he knows anything.