The Vault door is open, with various kinds of plants around the exterior and the insides. Vault 11 was a green vault keeping all the dwellers nice and fed until the scientists found that mutagen products were seeping through the vents which caused spores that flew without the vault infecting dwellers and thus killing them and turning them into some sort of animal like creature known a spore carrior there weakness being fire and lots of it.
The dwellers that were not infected escaped the vault and the overseer of the vault seemed to have escaped with the rest of the dwellers thus the spore creatures in there were small assumeing that they were babys or small children.
The vaults armory however is still there loaded with weapons and food and shiny rocks. the vault can be found near Cackledale and its also in a Jungle.
Also the vault seems to be unfinished in a sense that some levels are uneffected by the plant growth and others are. the vault has 6 levels in it and still be explored Today.