vadano third-person plural present subjunctive of andare
GO !! is something like Andare/Andate I believe.
It's odd. The present answer is via uomini which I don't recognoise at all though vai is 2nd person singular imperative of andare. vadono is 3rd person plural imperative so I still don't see why you can't use it.
When the wretched Captain Schettino was instructed to go back aboard his ship the command was vada a bordo cazzo!. But if there had been half a dozen officers sitting in the lifeboat what would the corresponding instruction have been?
On my multiple choice the answer was "Forza uomini" . It's more of a slogan (in soccer etc) than a literal translation I think.
via is away. I think they were going for something like "Away/Off with you MEN!" (Totally making this up)