After finally meeting the Alien for the first time, I have to backtrack and hack the big door in the main lobby to proceed, except it's being guarded by four or five armed men, and after being stuck for literally an hour I decided to have a glance at a guide online. Turns out the Alien should've showed up and killed them all, and I then have to dodge just the Alien and hack the door. In fact, as I enter the room, I can actually hear the gunshots and screams as the Alien tears them apart, but when I get inside, the people are still there patrolling, and there's no Alien. With them there it's impossible to proceed because no matter what I do they spot me while I'm trying to hack the door. I've tried reloading and the same thing happens every time. From what I've read the Alien's appearance here is a scripted event, but it won't trigger
Any ideas?