I just got to the part where you get off the train and you go with that guy to the air filtration system. He tells you to go up some stairs to fix it by hand or some junk and the door your supposed to clearly go through wont open. I even went to a quick walkthrough on youtube to see if that was the right way and lo and behold the same door will not open. Even tried reloading a save but it still didnt work. This game keeps disappointing me more and more. Anyone know of the same glitch or how make this work?