"The human mind," mused Romana as she followed the Doctor around the TARDIS console. "All in all, rather a rudimentary device for interfacing with reality."

"Yes," said the Doctor. "Fortunately, the mind of a Time Lord is a good sight tidier. My brain is a model." He pressed a yellow button.

“Of course it is, Doctor," said Romana, reaching forward quickly to press the yellow button again. "I mean, I'm not even slightly disorganized." He pulled a lever; Romana reversed its position. "One has to keep the brain clear, it's essential." Suddenly he looked up. "Romana!"

"What?"

He put a hand to his hair. "I've left my hat behind!"

Romana smiled, took the hat from her coat pocket, and popped it on his head.