Yeah, many snakes like to hit their prey from a secure location like their hide or a perch. Rats are naturally curious but it could have also been hungry, which would explain the digging around after taking a little test nibble - more like a lick with barely any pressure - on the snake's nose. You did right by removing it, that feed was going nowhere fast. If the rat was indeed hungry each test nibble would have been a bit harder until it hit paydirt or met his own demise - either scenario depending entirely on the snake's reaction to the situation. If you try live again, don't mess with the snake before offering - especially since it's a new animal and still adjusting to her surroundings. Without exposing the snake the rat would have likely made a few passes by the hide entrance while exploring, giving your snake a chance at an ambush if she was hungry and settled enough to accept.
The same principles apply when offering f/t or prekilled if you go that route. Until your girl is a strong feeder, and even after, you want to mess with her as little as possible during a feed.