1. Vault Role-play event, driven by players and GMs .
GM would type player into Overseer role, there will be murder in the Vault, some guys want to help to hide him, some want to reveal, Overseer's job is to find him, Murder's job will be killing Overseer. Also there could be some players intrigued to escape from vault, and those who don't want to get it opened.
2.Vault Survival event.
Players will be drop to last level of vault, given SIMPLE equipment, and their mission is to get their way to surface, they need to obtain some items during this event to continue their way to esacpe, repairing elevator etc.
Enemies could come in waves (walkers zombies, average with power fists, weak running zombies with spiked knuckless, and boss at end , big one with mega power fist which got key to surface.