The ending of Welcome to Raccoon City shows the survivors outrunning both a monster and an official lie. As the city is destroyed, the train is damaged and the mutated Birkin chases them, until Leon kills him with a rocket launcher. Claire, Chris, Jill, Leon and Birkin's young daughter Sherry leave the tunnel alive, even though Umbrella has reported no survivors.
That last detail is the point. In my opinion, the film is setting up a cover-up story rather than a victory, because a company that has already erased a town has every reason to silence the people who saw it happen. Claire opens the film trying to warn Chris about Umbrella, and she closes it as proof that the warning was right.
It could be argued that the rocket launcher finish is the film's most honest moment, since it hands Leon, the rookie, a decisive act on his first night. The weapon is a nod to how the games let a prepared player finish a boss, and it gives the film a payoff that a monster chase on a damaged train needs. Perhaps the better question is what Umbrella does next, which the post credit scene starts to answer.
Compare how the Anderson films close. Resident Evil: Apocalypse also ends with Raccoon City destroyed, but Alice is the one who walks out and the story keeps going with her. Here nobody carries a superpower, so the survivors are a group of ordinary people with one unlikely escape and a company denying they exist. As such, this ending plays closer to a siege film than to the franchise habit of ending on a bigger war.
The cost of the small scale is that Wesker, Ada and Umbrella's plans are left open, and the film earned only $41.9 million worldwide, so no sequel followed. For how this fits the wider story, see the Resident Evil timeline.