1. Cathica learns something.
In the beginning, Cathica is ordinary. She is a journalist who doesn’t ask questions. She has a good job, she obeys the rules, she vies for promotion just like everyone else. She lives her life, keeps her head down, and doesn’t question how – or if – the system works.
By the end, Cathica is beginning to ask questions. She is digging for the truth. She is standing up for what she thinks is right.
2. Cathica saves the day.
Cathica’s interference distracts the Editor, allowing Rose and the Doctor to escape. She kills the monster and liberates her people. She does it using her skills as a journalist – discovering and applying information – and her new-found courage.
3. Cathica lives to fight the next battle.
So often, those ordinary souls who step up to help the Doctor give their lives in the process: Jabe, Gwyneth, De Maggio, Pete Tyler, Lynda Moss, even Captain Jack. Cathica comes through unscathed, and like Harriet Jones, takes the Doctor’s place as hero in the aftermath.