Many would likely think her completely insane for remaining in his house when she knew what he was capable of. Maybe they were right, but she couldn't just walk away without having some sort of answer for what he'd done to her. Even the confusing snippets of facts that Gemma gave her before she was murdered didn't make much sense. There was always the possibility that Gemma was indeed a liar and Rodolphus was simply tired of her being there. If she ran away, she would be back where she started. And it wasn't as if she couldn't take care of herself. She hadn't been a Death Eater for twenty years just because the Dark Lord liked to keep her as a pet. She had to earn her place in the Inner Circle, earn her Dark Mark. Nothing was ever just handed to someone in their society. She wasn't some weakling who couldn't defend herself.