Not sure, but the Director of Top Secret Research and Wally pretending to be working like a spy could be references to Wally passing himself off to the PHB as a "g-man" (a CIA, FBI, or other government operative for those not familiar with the American slang). Hence a subtle joke about about receiving a mysterious email by a "g-man" from his "gmail" account.
Or maybe I'm reading too much into it. It is after midnight right now.
Kind of ironical, isn't it?
Nowadays, GMail is not known for its secrecy or, to be more specific, the way it handles a user's private data. And to have 'The Director of the Top Secret Research Group' use a GMail ID for official correspondence is simply contradictory. Wally has not been following the latest technology news & trends...