Sarah Brook

Dr. Sarah Brook is the only human crew member sent to Europa by the ISA that we know for sure to be alive.

Spoilers
At the end of chapter 4, Sarah contacts Ava though screen messages and a short video play to warns her about T.O.M. Then, she brings Ava to a Faraday Cage where she can be free of its influence.

In an early secret chamber, there is a child's tomb with the family name Brooks. An audio log later in the game confirms that Sarah became unexpectedly pregnant.

In one of the audio logs, on the catwalk stairs by the end of chapter 7, we hear Sarah begging TOM in despair, then when, it let Chris McLean die of what sounds like suffocation, we hear her horrified cries.

In another log, TOM express what appears like geniune regrets for having hurt Sarah's feelings.

In the Epilogue, Ava rejoins Sarah who removes her implant, making TOM unable to track them when they both go to its server room to dismantle it.

Trivia
Sarah Brook is voiced by Amelia Tyler.