
One of the things that Gertrude does seem to fear is her own death. In the tape she intends to leave to her successor, she at first tries to beat around the bush about WHY she would need to leave a tape behind. She starts to say that it’s “likely” that she’s dead, before giving up and admitting that if someone’s listening to that tape it means she’s gone.
It’s an important detail because Gertrude is a character who’s usually very thoughtful in what she does, and in a certain way very careful about how she portrays herself to others. The fact that this little moment of vulnerability slips out seems to imply that facing the reality of her morality is something that frazzles her a bit, and I think we get a little more implication in this in the “Dreamer,” where Oliver Banks dreams about Gertrude’s impending death. He says “It was your face and the expression upon it was far more fearful than any I had seen in eight years of wandering this twilight city.”
So Gertrude did not go peaceful into the good night, which is an interesting aspect of a character who’s usually shown to be so unshakable. Even she fears death, and there so many reasons you could speculate as to why. She could just have a normal and human fear about something that most of us worry about. She could fear the unknown as an Eye avatar who has spent her life dedicated to seeing everything she can. She could fear what would become of the world without her in it. Or she could fear everything in-between.
Personally, my headcanon is that Gertrude’s fear of death ties a bit into her savior complex. She worries about who will be there to save the world once she’s no longer in it. (Which, bonus headcanon, could tie into why she bound Gerard to the book.) And that’s why she looks so fearful when Oliver sees her. However, regardless of the reason I really like this addition to Gertrude’s normally stoic character. No matter how strong she was she just human at the end of the day, and she feared death just as much as any other.