Alfred: (under the Siren's spell, Commissioner Gordon has stowed away in the Batmobile after which it returned to the Batcave) Commissioner Gordon, what are you doing here?
Commissioner Gordon: You! You're Alfred, Millionaire Bruce Wayne's butler. And that voice! The same nameless voice that often answers the Batphone.
Alfred: I'm afraid you're making a mistake, sir.
Commissioner Gordon: Mistake? Nonsence! Obviously this is the Batcave... Ergo Batman is Bruce Wayne and Dick Grayson is Robin the Boy Wonder. Hmm hmm!