Le Doigt dans l'engrenage (1934)

Steve Wayne, a daring young ambulance driver for a large hospital in Los Angeles, is a rival with his friend, Doctor Bill Barie (the house surgeon in the Emergency Ward), for the attentions of nurse Martha Gray. Despite their rivalry, Steve still endeavors to free his friend from the grip of a merciless racketeer and a gambling gang. But Steve fails in his efforts and then sets out to avenge his friend and smash-up the gang.