Bonnie is the wife of Wayne Tournquist and the mother of Michael and David Tournquist. She was a nurse at Mass Bay Medical Center before, during and after the Great War. While her husband and sons made it to safety in their bunker at their suburban home in West Everett Estates, Bonnie could not leave the hospital; as the military had taken over the hospital after the bombings as well as a large amount of casualties pouring into the hospital. Bonnie and the other nurses could do little to treat their patients and sometime following the war, Bonnie and some of the others apparently left. From Wayne's logs we know that Bonnie never made it home. Judging by the chaos that ensured after the bombings, Bonnie was likely killed while trying to get home.
Bonnie Tournquist does not actually appear in the game, but is mentioned in Wayne's terminal logs and her holotape.