It's that sound, it's stuck in your head, what if I could help-
[The Master abruptly cuts him off]
Oh, how to shut him up? I know, memory lane! Professor Lazarus, remember him, with his, "Genetic Manipulation Device"? [Flashback appears] Did you think little Tish got that job merely by coinsidence? I've been laying traps for you all this time, and if I can concentrate all of that Lazarus Technology into one...little...Screwdriver. [The Doctor Stares, shocked.] But, oooh, if only I had The Doctor's biological code...W-wait a minute, I do! [Clicks] I've got his hand! And if Lazarus made himself younger, then what if we reverse it, another, what? Hundred years? [The Master violently points his laser screwdriver at the Doctor and starts aging him.]