The Doctor backed around the console, trying to keep some distance between himself and the thing that was currently trying to gnaw on his skull. "There was a sign on that door," he complained, "I wrote it out myself. It said 'Not to be opened. Beware of the Zombies.'"
"I thought it was one of your little jokes," said Donna swatting at a zombie with her shoe.
"No, no, you don't want my brain. Eat Martha's brain, she's a doctor."
"Oi," objected Martha, who was standing on the TARDIS seat keeping a zombie at bay by jabbing it in the eye with a hyperspacial spanner. "What have I ever done to you?"
"Sorry," Donna actually looked a little contrite as the zombie who'd been menacing her lumbered over to Martha.
"Better yet," Martha addressed the zombies, "eat the Doctor's brain. Time Lord brains, yum yum."
"Hey, what did I do to deserve that?"
The Doctor had to admire Martha's ability to get words '1913, 1969 and walking a post apocalyptic earth for a sodding year by myself' across with only a raised eyebrow.
"Oh, yes, that. Here zombies, good zombies…"