For the second time in one day the Overseer needed extensive repairs. She was resting in her personal Autodoc, 'dreaming' of a past life. She recalled the early times when she assumed command of Vault 121 as the Overseer. The preparations were finally over and the Vault was officially opened to basically anyone interested in living and working underground.
"A better life, underground."
She remembered the old Vault-Tec posters... What a joke! Vaults were never built to save people. They were just twisted social experiments carried out by the U.S. government with the purpose of sending people to Mars one day. Her Vault was going to be different. No secrets experiments there; only hard work. She wanted to do good, but the Wasteland was a harsh, unforgiving place. Not even 24 hours passed since she opened her Vault to the public and she had to seal it.
A heavy rain of missiles fell from the sky that night and leveled Tenpenny Tower. The most glamorous place in the Wasteland was now in ruins. The Overseer suspected the Enclave was behind the atrocious attack. Only them had the motive and the fire power to lead a full frontal assault on the new Vault. The synth was angry, but there was nothing she could do at the time, but try her best to keep her people safe.
Going even further back, the Overseer remembered her time at Vault-Tec. She was the prototype, the Original. The infamous Institute wasn't even created. She was the first of her kind and, as far as she knows, the only one. Today she's 236 years old. She had many fights, many near-death experiences, but somehow she survived them all.
Going forward in time to the Enclave attack, she remembers when the ceiling of the Vault's entrance collapsed, after a direct hit from a nuclear missile. Security rushed in to fend off the ghouls that broke in through the ceiling. However, some poor bastard fired a mini-nuke in there. Everyone died. The second hydraulic door wasn't going to keep the radiation away for much longer, so the Overseer asked for volunteers.
Nine brave men worked the entire night to seal off the entrance from the rest of the Vault by filling it with lead and concrete. Those men were heroes; the Vault owes them everything. Being exposed to deadly levels of radiation, the volunteers were beyond recovery. The Overseer remembers clearly when she asked their families and friends to go visit the infirmary and say goodbye to them, while they still can. The synth was overwhelmed by the dedication and the incredible sacrifice of the humans. It was the first time she had witnessed something like that. Now she's feeling regret for programming the Vault to kill everyone inside in case people try to overthrown her.
It was a safety measure she thought of because she didn't trusted humans. The security system of the Vault was connected to her positronic brain at all times. If they try to kill her, if they try to isolate her, or do anything that could break that connection, the automatic turrets of the Vault are programmed to activate by themselves and open fire, after a specific time. They will all die. If they try to cut off the power, the will need boot-up passwords to start the reactors. The Overseer thought of everything. Expect that nothing prepared her for witnessing the brave sacrifice of those vault dwellers. Now she's conflicted; everything she took for granted thrown out the window, so to speak.
But there was no time for mediation; she'll have to think about all that later. Right now, there's work to do. This is their life now: underground, hidden, like rats. And the faster they accept it, the better. Everyone should contribute; they're all in this together. The following day, the Overseer assigned jobs to everyone, with the help of the GOAT. She remembers thinking: "The future is how we make it. There are no worthless jobs and no worthless people. Except those without jobs."