Well, none of the flour was disturbed that I laid out last night. I had put flour line across the doorways of the rooms and entrances to the kitchen. So I think she must still be in whatever room she's been in.
I also tried putting a hide with a heat lamp over it since the AC is nearly always on now because of this heat wave (100 F at 700pm). No luck with that. I also left her tank open in case she decided to go back home.
So, it looks like this weekend will be dedicated to turning our apartment upside down to find her. I am really hoping the she couldn't have squeeze under the door to the water heater closet as there are open drains in there. I doubt it though since I can barely get my pinky finger to fit under the door.
This is so frustrating...