This story-related Achievement is awarded at the end of Chapter 15 if you leave your team members to burn.
When you escort Jenny to the helicopter, you have a choice to make that determines the ending of the game. If you choose to board the helicopter, this Achievement will be unlocked.
This can be earned on any difficulty level, so drop down to easy if you're having troubles, or just want to earn it more easily.
If you pause the game and restart the scene immediately after this Achievement unlocks, you will start where you need to just board the plane and rescue Jenny. You can then choose to return to the village and work for the "Damned if you don't" Achievement without replaying the entire Chapter.