Brielle had been on her own, surviving. Until a hoard came and chased her out. She got saved by Delta Xray Delta. Murphy and her do not get along and 10k likes her for her quick wit.
As the group finally gets to Mount Casey, Rosie Garnett starts feeling the effects of the vaccine that Warren injected in her start to kick in. 10k realizes he's about to lose a person that cared about him the most.
Takes place in season 3 of Z Nation, from the episode "Everybody Dies In The End."