That's a weird one, Serena. Not sure I'm picturing exactly what's happening... What you might want to do is see if you can catch it on video--even if it means camping out next to her with the camera
. The chances of Keely doing it while at the vet are probably pretty slim so having a video might be very helpful.
Good luck at the vet tomorrow! And as long as otherwise she seems pretty much normal, try not to worry too