» Tue Sep 22, 2009 1:41 am
I think I found the best explanation on the wiki "The Vault" I quote the website
"Vault 87 can only be accessed through Little Lamplight. The player will have the option of questioning mayor MacCready about how to access Vault 87. The mayor will suggest taking Murder Pass. However, he will also inform the player that there is a broken computer terminal in Little Lamplight that will allow direct access to the Vault via a different, safer route.
To access the terminal, the player must speak to Joseph (as directed by the mayor). Joseph can fix the broken terminal, allowing it to be hacked, but he will only do so if the player has rescued Penny from Paradise Falls, if the player has a high enough science or persuasion skill, or through the Child at Heart perk. Joseph can be found in the Little Lamplight schoolhouse in the morning. The player must have a science skill of 50 to actually hack the computer to get into the Vault.
If Penny is not rescued, or if Joseph becomes upset through dialogue, entrance through Murder Pass will be the only option to get to Vault 87. Located North of the souvenir building, Murder Pass houses several super mutants armed with heavy weaponry like missile launchers and miniguns. There are also a number of traps, so be careful. Mayor MacCready will open the gate for you if asked. Murder Pass is a good choice for earning experience. It also contains several medical cabinets, a decent amount of ammunition and a Nuka-Cola Quantum."