We found her! She had apparently snuck into the garage and must have been startled by the cars and the garage door sounds and hid. This morning we heard loud mewing and when we opened the door she came running in.
So, everything is fine!
--ORIGINAL POST--
Sloane appears to have run away. She must have slipped out an open door at some point and nobody noticed.
I have little hope that she'll find her way back as she's never been outside. She's chipped so if someone picks her up and takes her to a vet / pound there's a chance she could be back, but I'm not holding my breath.
I at least hope some nice home takes her in and takes care of her.
She will be missed.