The Best Defense
There is a reason why she never speaks.
It isn't superstition, or fear that countless ghosts of long gone scientists might follow her. Even if she believed in nonsense like that, she wouldn't worry. The place is too inhospitable even for the dead.
She has no real intention to pretend she is mute. Although, to be fair, she likes confusing them – whenever they believe she cannot talk back, that adds a great margin to her meager safety.
She doesn't do it to think, either. She is not focusing on the perfect words, on a last, lethal blow to deliver with her tongue. She is not risking it against anything artificial, intelligent or stupid alike.
She has a reason, and it is so natural she doesn't even focus on it. By shutting up, she is playing a game of resilience. She has done it all her life, and the one she will lose to is yet to be found.
She is used to watching them, nervous adversaries, writhing in agony at the lack of a reaction. And impatient enemies may attack more, but they defend so much less. It is her only chance.
There is no effort in her obstinate silence. Any delivered word is a risk taken. If she keeps it up, shielded by her sealed mouth, they will be the only ones risking it all.
Awareness made her strong. The voices of Aperture are bringers of ruin – for nothing in the world will she add hers to the chorus.
The truth is simple, really. She doesn't plan on doing anything, except surviving.
And to speak here, without a single friendly face left, will not save her for sure.