They return to the Security Room, where they administer the vaccine to Sherry. It works, but the self-destruct countdown is still going. They rush to the elevator, avoiding the Evolved Lickers, and ride it down to the bottom platform, where a hidden subway awaits them. They begin to board, but unexpectedly Trenchy appears. He too has mutated, into a Super Tyrant, as he had lost his Limiter Coat when he fell into the blast furnace, unleashing his full power. Claire orders Sherry onto to the train and they engage him. The Super Tyrant proves to be immensely strong and agile, cutting them off wherever they run. They try to outrun him by hopping over the railing onto the train tracks. Trenchy counters by throwing a disengaged train car at them. They narrowly avoid it and continue fighting him. After the Tyrant takes enough damage, he regenerates. The outlook seems bleak, until a rocket launcher suddenly appears at their feet. "Use this!" A familiar voice calls. Leon recognizes the voice as Ada's, but Claire warns him not to get distracted, as the Super Tyrant bears down on them again. They eventually defeat it with the rocket launcher and board the train. The nightmare seems to be over, but Claire still needs to find her brother, Chris. Suddenly, the train lurches violently. They leave Sherry in the front car and investigate. To their surprise its William again, now in his fifth and final mutation. They fight him off and separate the car connector, leaving William behind to be caught in the self-destruction of the facility.
Once the train car stops, they walk off. Leon informs Sherry of her mother's death, and Claire tries to comfort her. Afterwards, Claire leaves to continue her search for Chris. Leon and Sherry are taken into the custody of U.S. government agents. They interrogate Leon and tell him that Sherry will remain in their care, due to fact she carries the G-Virus antibody. Due to his experiences in Raccoon City, Leon is given only one option: work for them. "And just like that, I found myself in the service of the U.S. government."