In Jean-Pierre Melville's 1970 French noir thriller Le Cercle Rouge (The Red Circle), the protagonists, two robbers, plan a daring heist in a downtown Parisian jewellery store. They are seasoned criminals, still they hire a former cop to help them as marksman and use his experience as a sure-fire getaway ticket. He comes more than handy.
A cop on the wrong side of the law is the greatest challenge for police. He knows the system's limitations and exploits its chinks to the fullest. Dismissed senior inspector Arun Borude, on the run for over three weeks after having been found to be involved in the rape of a minor last month, is doing just that.

Please explain to me the highlighted parts.

Source : Mumbai Mirror
Hi , Gary.

Noir is a a genre of crime film or fiction characterized by cynicism, fatalism, and moral ambiguity.[dictionary]

Sure-fire means "faultless, infallible".

Sure-fire getaway ticket is a guarantee, fail-safe chance to ensure their escape.