Dog Bite Dog (2006)

A Cambodian man trained to fight for gamblers in his country is hired as a hitman and sent to Hong Kong. He performs the hit and then has to flee from Hong Kong police, who are wrestling with internal problems involving a model cop and his son, who is also on the force and who'd been told by his dad not to become a police officer. The model cop is in a coma after being shot, and internal affairs suspects him of dealing drugs on the side. The assassin then befriends a young girl who is molested and abused by her father. They both plan to get back on a ship to Cambodia but have to get past Hong Kong police, who are doing everything they can to catch the assassin.