Gun of Mercy (2008)

As the local rivers swell and the urban population is evacuated, a retired policeman escorting three dangerous convicts to another institution finds a simple transportation job complicated by the rapidly worsening natural disaster. The local riverbanks are about to burst, and in order to ensure that three prisoners don't face a watery demise, retired cop Lao Ma is asked to transport the men to safer surroundings. Among Lao Ma's charges is a convicted killer currently awaiting execution, a notorious embezzler rumored to have hidden his fortune before serving his time, and a stone faced thief whose parole date is just on the horizon. When the waterlogged countryside roads prove impassable and the four men are forced to work together to make it through the night alive, the nervous lawman realizes that his gun is the only thing keeping him in charge, and he's only got five rounds of authority left.