So I had the idea tonight that if you are in say vault 84 completing encounters. Does this still mean you can be attacked while you are in the vault space? Technically I am in a vault right? And therefore monsters do not enter?

This game is too simple and it lacks that kind of depth. Rules as written, monsters attack you even in a walled off city or underground bunker. But nothing is stopping you from house ruling it... it's better as a narrative experience than a competitive game, anyway.

Who's saying the monster wasn't intentionally let into the vault? I wouldn't put it past vault-tec to 'test' some vaults for unexpected incursions.

10 hours ago, Astech said:

Who's saying the monster wasn't intentionally let into the vault? I wouldn't put it past vault-tec to 'test' some vaults for unexpected incursions.

+1

Or who's to say your character doesn't "pop out for a breath of fresh air" every now and then.