What happens in the beginning of Resident Evil 3: Nemesis?
After the CGI intro, and the typewriting / narration of Jill Valentine, she gets some sort of blown into the streets and that's when you, the player, take control of her.
What led to that explosion? Where was she? And why didn't that explosion affect her in any way?
An interesting answer seems to have been provided from the books if you consider those to be canon. Not entirely sure which book, though;
"In the book, there was a gas leak in the apartment building. Jill ended up needing to shoot a zombie while inside and everything went bang." — Splatterhouse5