Where is mercenary mode in Resident Evil zero

There is no mercenary mode in Resident Evil Zero. However, you can play Normal mode and beat the game in under 3 hours. You can get the Infinite Rocket Launcher. You will also get the Closet Key. The closet is in the train. When you go get the Ice Pick for whoever is trapped, go up the hall and through the door. You will see a door. Go to the door and open your inventory and use the key. You can change that person's clothes. Billy can only go in one costume so wear it if you want. As for Rebecca, you get two choices. She can either go in a Leather costume (personally I don't like it) and a Cowgirl outfit (seen in Resident Evil Remake for the Gamecube if you change Chris's clothes).