This is technically missable but you'd have to be pretty impatient to pull it off.
While evading the ferocious creature in Tau, you will pass through 2 large red doors that take an eternity to open. Once past these your next goal is to pass the door labeled "Infirmary." That is our target, once past this and up a ladder you will meet the last living human. Speak to her and it will trigger.
This is missable as talking to her triggers the trophy and you could hypothetically walk in the room and immediately turn off her life support. But...like don't.