Unmissable Storyline achievement. Description is a little misleading. It won't pop until you have killed her or walked away.
Remember not to kill her If you're going for;
https://www.trueachievements.com/a222445/savior-achievementNot killing her will also help towards;
https://www.trueachievements.com/a222443/look-at-you-hacker-...Aside from that, I don't know what loot she drops, but she gives you aid packages a couple times in the story, so I advise not killing her if you're worried about difficulty.