Probably because Zuzane never revealed you their plan once you escaped the mine
What breaks the quest at one point is killing or fighting the miners inside the mine. Objective clearly states “RUN” just after Nimoy was thrown down and killed. If you start killing miners i guess Zuzane then leaves the camp or just stay silent (if still there) because shes scared of you that maybe you can kill her too.
To finish the quest in the proper way you just have to run inside the mine, avoid folks at all cost and then show up again at the camp.
I personally didnt take her captive. First because she said she killed Nimoy to save you. They (miners) had an argument and wanted to kill you, being Henry a witness, and she didnt want it to happen. Second because im filthy rich and i dont need extra grosschen. Third because shes not a bad person