This takes place on Episode 8 - Sovereign Land, and is attained by reaching your gear inside the trailer park without instigating combat. Sneak into the trailer park by jumping over the concrete fence on the left hand side. Once inside, sneak your way into the middle trailer where the main objective is, and interact with the gear to unlock the achievement/trophy. If you are about to be spotted, you can quickly reload the checkpoint. Remember that you can through bullets to distract guards and make them turn around if you need it!
*Posting for MAKA91, because he is only playing the Xbox One version.