I think it being a time machine trumps its being powered by plutonium: go to future for cure to cancer, come back, and just like that, the plutonium is irrelevant.
the joke is why you're still depending on some manager's opinion, bringing it to his office (for what? for demo? for approval?) when you have invented time machine.
There's a potential non-technical problem with that solution, though - what happens when the person who controls that email address leaves the company, especially if they leave on bad terms? I've had to deal with figuring out the mystery email that was connected to a corporate social media account, and it was a hellish bureaucratic nightmare to find the social media intern from three summers ago who had the password for the throwaway email. If it had been an email from our corporate domain, it would have been a lot easier to gain control of it again.
(What I would have given for a physical, printed list of social media accounts, associated emails, and passwords hidden in a file drawer somewhere.)
