I've been stuck at the water plant in Chapter 3. Checked the video guide, and I had already done exactly what the video guide did...
https://youtu.be/aDLGw63CYPM
...Up until the part where they entered the small grey building you see when you first enter this section. For some reason, despite picking up the key from Pool 4, that door won't unlock. And neither will the door in the pool room itself, so I can't just skip this part and try fixing the water station in another playthrough.
I tried reloading a save from the top of the elevator at the end of the previous section. I've tried verifying the integrity of the game cache multiple times. I've even completely uninstalled and reinstalled the game. Nothing seems to fix it.