So... Vault 87's entrance took a direct hit from a nuke...
...and was rendered unusable (it says so on a terminal inside the vault).
So
1) How did the dead scientist get where she is - straight outside the vault cave entrance? The vault entrance is collapsed and unusable, after all... Surely she didn't trek all the way through Little Lamplight? And then what would the point be to go to the cave entrance, which they already knew were nuked and unusable?
2) Who put up the "high radiation" warning signs we see close to the vault? Surely not the super mutants, since they are immune to radiation...