Search for Clues to Bypass Security Walkthrough
First thing to do, if you are already not there, is travel back to Fort Defiance. Once there head to the back north end of the building and up the broken roof that creates a nice ramp.
Take the ramp up to the second floor, there will be some junk to scrap for crafting, but to get to where you need to go you can take a short cut by walking against the wall where the floor collapsed (the same floor you used as a ramp). There is a small ledge sticking out, use that to cross the gap to the other side. Once you cross the gap take the first door on your right, there will be a set of stairs you can take to the Third floor.
Once you’re at the third floor, you will once again see the laser-grid guarded elevator. Interact with the terminal across from it and activate the scan under the option Register New Personnel. It will fail because you lack the proper ID. Continue to search the 3rd floor for clues on how to bypass the security grid.
In the West end of the third floor there is a barracks across from a bathroom. Inside the barracks on the bottom shelf of the metal shelving at the end of the room titled “Squire Evelyn’s Journal-Page 16”.
This note reveals you need a government issued ID to enter through the laser grid. If you already have completed Back to Basic, you have one half of the necessary government ID. The other half necessary is going to be a Government issued Drivers license…Looks like your’e going to have to go to the DMV.