Doofus was somewhat confused that after leaving a message for Mr Behr at the London Institute of Zoology he hadn't called her back:

Doofus: That person you left me the message for didn’t call back.
TKK (for it is he): Which person?
D: Mr Behr.
TKK: Mr Behr? He didn’t call you back?
D: No. Are you sure he was asking for me?
TKK: Well he had your number.
D: Maybe he made a mistake?
TKK: Mr Behr made the mistake?
D: Yes.

At this point one of my colleagues (who was in on the joke) left the room because the effort of trying not to laugh was becoming painful for her.