Whenever a cat is moved it immediately scopes out a safe spot where it can hide until its sure there are no predators or dangers.If you ever saw a new cat go into the cat room of a shelter you would see her go under something or up as high as she could climb.
She most likely walks around at night when it is quiet and everyone's asleep.
I would forget about the trap. Just put food, water and a litter box on the floor.
The cat will come out to eat, drink and potty at night when sh e feels safe.
After a few days she will venture out into the rest of the house. It can take up to a week to acclimate.
As long as she is eating just give her some time to feel comfortable and she will come out.If you have other pets try to keep them out of that room.
I would get a feliway plug-in to keep her calm.
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