@fuyuhakai
You clearly didn't understood her character....
What broke her was not the death of the pet but the idea that it could be easily replaced.
Her whole character was about being irreplaceble and the fear of being replaced leading a person to... well insanity could be used here but that was not really what happened.
Reseach on undead is actually a very beneficial one when conducted correctly, as it would give a untiring free work force for simple manual tasks.
You are right she was a bitch but not on what made her be like that. She is a way deeper character than you are giving credit. The "everything is easily replaceble" is a premise so good that there is an anime that is based on that called "Suzumya Haruhi no yuutsu".