In "The Family of Blood" Dr. Who temporarily changes into a human, in a WWI boarding school for boys, locking his power away into a pocketwatch. He leaves a video for his Companion, Martha Jones with instructions on what to do while he's "away." During the episode we only hear the first few instructions, and then the one at the end. Well here's the full video of it.
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And it's "pears," not "Pez."