This is completed in Chapter 2. In case the video goes down, towards the end of the chapter, you'll be leaving the P-Sec building. After you meet Lexine after dealing with some necromorphs, you'll ride an elevator down to this storeroom. Once you exit the elevator, you'll be in Free-View to look around, turn to the left, ignore the ammo lying around and look at the door. There is a purple fuse box, shoot it to gain access to the storeroom. Don't be fooled by the 'Unlocked' display on the door, since the fuse box is technically locking it--it could be a glitched graphic or a subtle way to galvanize your attention. You only have a handful of seconds to do this before the game continues on. If you miss this opportunity, you can use the Chapter Select to re-play the level for another chance at this.
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