If you wear a tux under a wetsuit, will it stay dry and neat for the spy mission?

No, but are you sure it was a wetsuit rather than a drysuit?

I'm guessing you've never worn a wetsuit, right? It's called a "wet" suit for a reason.

A drysuit, however, is another matter. That might be feasable, but the tux is going to get awfully wrinkled.

Edit: DOH!

have they done this one??

Nope.