After finishing the performance with Steph and comforting Charolette on the docks, make your way back to the "The Black Lantern". In the same area where you found both the "Umbrella" and "Bomber Jacket" memories, look to your right once you enter that area. To the left of a military service photo is the "Polaroid" memory that you'll need to interact with. Hold
and then the
button, listen to the memory play out and the achievement will pop!