She and Susan would often encounter bully named Francis Minto. "F.M." had a history of destroying the snowmen they made. One day in particular, however, the snowman he attacked did not des integrate, but water came to life, and started attacking him. He was put in the hospital after this ordeal, and Susan and Gillian were punished with detention for a week.
One night Gillian and Susan went off to a club attempting to pass off as adults. There they met Zack, a bike rider who tricked Susan into admitting that they were too young to be there.
She enjoyed giving nicknames to the people she knew. She would often call John "The Martian" and Susan "Forehead." She was also a skilled fighter, often getting into school fights. She found it hard to be grateful for John's father's sacrifice to save her life, calling him "crazy."
Over the time of the Cold's existance on Earth, Susan and Gillian's friendship soured. When it came to the exsist ance of the human race, she used Susan's life as a threat to get the First Doctor to help them. (TN: Time and Relative)