Gat was a Gallifreyan who worked with the Doctor. She worked with the Judoon to capture the Doctor.
When she captured the Doctor, Gat was surprised when she was confronted with the Thirteenth Doctor. She cited the Blinovitch Limitation Effect, terming it an "abomination."
She was horrified when the Doctor told her Gallifrey was gone, presuming she was lying
She was killed when she tried to shoot the Doctor with a laser rifle as it had been calibrated to shoot the one holding the gun. (TV: Fugitive of the Judoon)