Let me fucking guess. The mummy somehow has some anti effect against the poison, because the woman used to be a mother or big sister, and the crazy experimentation is to try and bring them back to life in sheer delusion? That or she has anti poison near it, cause she injects it on the mummy when the experiment doesn't work.
The girl is gonna bring the mummy, and basically threaten to "end it", the psycho bitch is gonna freak the fuck out and threaten to blast the brains out of the villain cause she somehow values the mummy more, and forces the goons to give her the antidote. Or something like that.