I spent a couple of hours yesterday fighting my way through vault-tec HQ and literally scouring the place for loot and other items of value.... when I came across the mainframe shutdown terminals. I got access to the mainframe terminal approved on all 3 remote terminals but when I got to the mainframe door it was locked and its one of those annoying doors you cant pick and you must have the key. I have two questions here.... Where can I find the key? and My next question, is it worth my time, as in what happens when I shut down the vault-tec mainframe?. Created by Anónimo. entertainment-music-ar - other-entertainment-ar

This is a known glitch. Have you updated to the latest patch? Try going back to each of the terminals and activating the door again, in order. The reward for getting through that door is that the locations of all the Vaults in the Wasteland will be uploaded to your PipBoy map. 87, 94, 106, 108 and 112. That's it.