@19centuryman The Jungle? The Ragged-Trousered Philanthropists? War and Peace?
The favoured response of Greek ultra-nationalists:
... when challenged about their criminal past (in this case, armed robbery).
@C_Webb Yes. MB is like the actual pointy carving bit of the Awl.
'Carry on' is also the stereotypical phrase used by officers in the British Army, when passing control of a job to a non-commissioned rank (as in the first of the titular films):
For any ex-servicemen (plenty around from WW1), there'd have been a kind of subliminal kicker to the poster: 'get on with it (but also, I trust you to get on with it unsupervised and will now leave and stop bothering you)'.
It sounds like it might have been an escapee from a local fighting ring. They're pumped full of rat hormones.