Hitman from Today Rising

This salaryman is a former underworld hitman! Food company salesman Tokichi Inaba was once a feared hitman nicknamed "Nidō." Just when he thought he had completely cut ties with the underworld, one day he finds himself strapped to a bomb, forced to carry a gun, and forced to take on a life-threatening, shady part-time job! (Source: Kadokawa, translated)