War. War never changes.
This is why the Royal sisters wanted to be prepared for the next nuclear war by building the vaults. Giant vaults made to shelter civilisation from the nuclear radiation so equestria had a chance.
Vault-tec was introduced to build these vaults and sort ponies into them based on age or species so they would be as comfortable as possible. What nopony told us was these vaults were made to test pony kind with various tests and experiments.
Vault 111 was made for cryostasis chambers so the war would last seconds for some ponies.
Vault 11 was made to test what would happen if ponies were told that if one pony wasn't sacrificed every year then life support would be shut down.
Vault 19 was separated into red and blue factions to see how paranoid ponies would react.
How do I know all this?
My names is twilight sparkle and I am the pony that designed the vault experiments.
Mane vaults
Twilight Sparkle
Year: 2060. 17 years before the bombs.
I got accepted into the vault program!
Princess Celestia asked for any young scientists who wanted to help preserve equestria to sign up and I was one of the ten accepted out of two thousand applicants.
I stood in front of the vault-tec compound with a few other ponies my age. We were all about to start talking when a pony in a lab coat stepped out and came towards us.
"Good morning! Welcome to vault-tec. I am the stallion in charge, In Genius, and I will be showing you to your personal quarters and design labs but first I need to take a quick register to see if every pony is present" he grinned "Moonlight Shines"
"Yes Dr.Genius" the dark purple mare called out
"Flame Dancer"
"Yes Dr.Genius"
"Creative Outlet"
"Yes Dr.Genius" the mare from trottingham smiled
"Dusk"
"Yes Dr.Genius" the male twin called out
"Dawn"
"Yes Dr.Genius" the female twin called out
"Cave Diver"
"Yes Dr.Genius"
"Scarlet Speedster"
"Yes Dr.Genius" a hyper red stallion called out
"Shady sands"
"Time Turner"
"Great wickering stallions yes Dr.Genius" the eccentric stallion I had seen talking to Derpy in ponyville yelled
"Yes Dr.Genius"
"Twilight sparkle"
My heart stopped for a second as he said my name. I was really here. I was going to help equestria survive.
"Yes Dr.Genius" I say with a burst of confidence
"if everyone is here then we can start work" In Genius turned and trotted towards the entrance to the vault-tec science lab.
The building was a futuristic white compound with spiralling escalators and 50 foot elevators.
We were each given a map of the area and now we have been showed into our rooms. It was a large room with plain white walls and furniture. A large box was on the centre of the floor and had WELCOME stamped on the top in big letters.
Inside are a few basic office supplies, a generic welcome to the company and then a schedule of when meals where and it told me that hours were flexible and I could work whenever I wanted as long as I had a vault concept by the end of the week.
I am ecstatic. I am really here, helping vault-tec develop ways to test the public so we have a master pony race as the survivors of the apocalypse.