Gun Woman (2014) on Netflix

Plot summary

Two assassins cross the desert toward an evacuation point, and one of them tells the story of a man known as Mastermind. Mastermind is a doctor who vows revenge after a sadistic killer murders his wife. The killer is protected by maximum security, and the doctor sees his chance when he buys Mayumi, a drug-addicted prostitute, and turns her into an assassin. Gun parts are implanted in her body, and she must assemble them into a weapon and use it on her target before she bleeds to death. The plan places her at the underground facility where the killer goes to satisfy his sexual fetishes.