Sheila Dunn credited as playing...
Dr. Petra Williams
- Brigadier Lethbridge Stewart: How long is all this going to take?
- Dr. Petra Williams: I don't know.
- Brigadier Lethbridge Stewart: Well can't you hurry it up. Dr. Williams?
- Dr. Petra Williams: No, not if I'm to do the job properly.
- Brigadier Lethbridge Stewart: You must, we've very little time.
- Dr. Petra Williams: Brigade Leader, I'm trying very hard to carry out a complex scientific task under impossible conditions. You will not help matters by bullying me.
- Brigadier Lethbridge Stewart: You are insolent, Dr. Williams
- Dr. Petra Williams: Am I? Then it's about time you learned that some problems just can't be solved by brute force and terror.
- [last lines]
- Liz Shaw: Go on, Doctor! Go now!
- Doctor Who: I can't! It's still too erratic!
- Dr. Petra Williams: [sees a giant wall of lava approaching the garage] GREG!