This is earned for finding optional collectible #1. If missed on the first run, you can "Play Episodes" and select specific parts of the Episode in order to find the missing optional photos through
collectibles mode. The following collectible is described and can be seen in the video below at 6:40
This is done during the heist and can be unlocked during either branch. There will be two different scenarios:
Option 1 - Planned heist with Finn and Daniel: You will reach a gate, that Daniel will open with powers. Check the 4 car doors to see if they are locked to begin a "search" segment. Search the yellow locker behind the pick-up truck, and have Daniel use power to open it. Inside, look at and take the "cartridge" on the top shelf.
Option 2 - Catching up with Cassidy: You will reach a fenced area with an open gate. Upon reaching a "search" segment, you may need to grab some tools from the bench, and then you can use these tools to break into a locker behind the pick-up truck. Take the bullets inside.
Getting all 6 collectibles in this episode will also reward you with the following:
https://www.trueachievements.com/a260746/lost-boys-chronicle...