Hmmm. Sorcery? That's a very loaded term, where I am from. Perhaps if you explain first, I can explain why she reacted as she did, from the perspective of a member of the Adeptus Mechanicus, a follower of the God-Emperor, and a servant of the Imperium. Because all of these will have different answers, to some degree.
[ Gaunt seems very mild. Then again, this is the man who punched out a fellow Guard Officer in front of an Inquisitor for insulting a dying Eldar, so he's a bit unorthodox to begin with. ]