It would be much easier for them to hide and wait in a dark place to turn the tables on their captor.
The captor could know the whole layout, but all it would take was missing something when walking through or being too slow to notice before they would be ambushed.
The idea did sound good in many ways, but it was still a risk to make use of that kind of place when she could just set up a kill room where they would be restrained and unable to fight back or escape.
It was better to maintain control over the captives to prevent any potential problems from arising.
She could not set up a place for her to bring her targets to, but she could make use of what was available to turn a location into a suitable kill room that would allow her to do such things.
If the door and windows were locked and blocked to prevent others from seeing inside and entering, then all she needed to do was to set up perception barriers inside the room of the building that she would be using.
