Can't hurt to try !!
Some are just so shy and insecure. They are hungry, but their nerves get the best of them.
When snakes constrict/eat they are at their most vulnerable. And they know it.
Some Ball Pythons are just to shy.
Make sure that once you leave the rat, there will be no more "activity" in front of the cage/tub. If need be, hang a towel over it. Just leave her completely undisturbed.
Some will eat the rat within an hour or so, but some will wait until the middle of the night.
I know the rat will cool completely during that time, but it seems some prefer that over eating while they feel unsafe..
Try it and let us know how it wentWe'll go from there..