On the Tiger's Back (1961)

Original title: A cavallo della tigre

Giacinto Rossi, a poor driver up to his neck in debt, is imprisoned for simulated crime. He finds himself in a cell with Tagliabue, an unscrupulous murderer; Sorcio, an elderly thief; and Papaleo, an honor-obsessed intellectual who murdered his fiancée's lover. Giacinto is forced by the three men to make a daring escape from prison.