SPOILERS -- things that change on the maps

[felixmole]

- After entering Tau, a message says the airlock is pressurizing, or something. What is that about? I thought it was supposed to be Yin Yoshida entering from outside, but I didn't find any entrance in the section he roams.

Spoiler below!

It's Ross entering from the Abyss behind you. Pretty sure the door stays open until you hit a checkpoint, then it closes.

Yes, the door closes at some point and you can hear activity in the airlock. You can see the door opening back up and Ross entering the room shortly afterwards.