I'm not convinced that she was "sick to her stomach". Maybe she was either always this way, or maybe the nature of the work has blunted her to this point, but she reminds me of psychopaths blending in. They know that the people around them have morality and that they're expected to have morality too, and they try to fake it, and often they get it fairly close, but sometimes they just get it wrong. Not saying she's a psychopath (there are many reasons to fake morality), but this jarring boundary in morality feels similar; makes me think it's faked.