I'm one of those people who has only ever played Fallout 3....and I'm a tad confused. The vault that it shows in the introduction movie, the one where the Enclave just opens fire and kills EVERYONE. Is that Vault 13?
I mean I'd kind of understand why they killed everyone in it if it was (I'm guessing the Enclave was in FO1), but if its not 13, then why the hell did the Enclave just start shooting?