Bitores Mendez will be formally fought at the Slaughterhouse in Chapter 2-3 of the main game. As the player approaches the barn a cutscene will play where Leon enters it himself and the chief ambushes him. The player must dodge his attack via a quick time event or they will get a game over scene. Being successful initiates the fight after the scene. Ashley will not be present during the fight, as she was left outside.
Various ammo is littered throughout the slaughterhouse during the fight. Leon can climb up the ladder to collect it, but Bitters Mendez will attack the player by stretching himself instead of climbing up the ladder also.
After sustaining enough damage, a cutscene will play where the top half of his body leaves his lower half and then the fight resumes. Mendez will now move around by wrapping his appendages around the horizontal beams and jumping from one to another and will now use a different set of attacks.
Upon defeat, Mendez will drop 30,000₧ and his False Eye. When the player picks up the False Eye, a short cutscene plays where Leon does so and then notices that part of the wall burns down. When gameplay resumes, there is now an exit and the player can use the "JUMP OUT" prompt to leave.