KARI: Why won't it move?

DOCTOR: It's controlled by the computer, and the computer's uncontrollable.

TURLOUGH: If ever you had to kill someone, could you do it? Could you?

TEGAN: No. I don't know. If it was important, to save my friend, to defend myself.

TURLOUGH: But cold-bloodedly?

TEGAN: You're weird, Turlough.