I'm glad you asked:

Vault-Tec designed Vault 111 to observe the effects of long-term cryogenic suspended animation on unsuspecting test subjects. Vault 111's staff consisted of an overseer and a small team of scientists, security guards, and facility maintenance personnel employed on a short-term basis. Test subjects were lured to Vault 111 from the nearby neighborhood of Sanctuary Hills and were placed in stasis pods after being told deceitfully that the purpose of the pods was for decontamination.

According to Vault-Tec standard operating procedures, Vault 111 was to remain sealed for a minimum of 180 days, after which the vault could be opened upon receipt of an "All-Clear Signal" from Vault-Tec or at the overseer's discretion. After the 180-day mandatory shelter period elapsed, Vault 111 received no all-clear signal and its staff faced dwindling supplies. The overseer, concerned that the radiation outside the vault had not declined enough over the past 180 days to be survivable, refused to unseal the vault door. Shortly after, a faction led by the vault's security staff engaged in mutiny against the overseer in an effort to unseal the vault door and to leave the vault. In response, the overseer placed the vault on lock down and asked all staff to hand over any food, weapons, and medicine. It is unclear whether the mutiny was successful as the logs end here on both the security terminal and the overseer's terminal.

After witnessing the murder of their spouse and the kidnapping of their child, the Sole Survivor awakens in Vault 111 after being held in cryogenic stasis for 210 years. Upon accessing the Vault 111 monitoring terminal, they learn that all of the other subjects that had entered the Vault, except for themself, their spouse and their child, had died, the causation being "asphyxiation due to life support failure." In the Dangerous Minds quest, the Sole Survivor discovers that the mercenary who shot their spouse, Conrad Kellogg, was directed not to reactivate the life support for the other residents and not to release them. 60 years later, due to an 'error' in Vault 111, the Sole Survivor is released from cryo-stasis and escapes. However, it is later revealed that the release was in fact a personal choice made by Shaun, now director of the Institute, and not an error of the Vault as initially thought.