You will get this Achievement in Chapter 5 after reuniting with Joseph you will come across a room that has Kidman stuck in a Trap filling with water. You have to keep her alive while protecting Joseph, he can't take a single hit of damage during your fight.
You will encounter alot of enemies ranging from normal ones to ones holding dynamite.
I dropped down from Survival to Easy for this video. I also only have a Shotgun, Pistol and 1 Explosive Bolt.