The Vault is one of the four original supervillain prisons operated by S.H.I.E.L.D.. It was built by Tony Stark and designed for technology based villains and as a storage facility for the villains' gear and weapons. HYDRA and A.I.M. have the most people locked up in the vault, along with their leaders.
Prisoners come in via the landing pad near the top, where they then go through a scanner and their gear is examined to see what kind of cell they belong in or if they are sneaking anything inside.
Normal tech villains are placed in standard holding cells with laser bars keeping them from escaping, while a few are specially designed for villains that are required to wear their gear to survive (example is the Blizzard & Living Laser). The more high profile villains are staged in solitary cells further down the tower, each designed to that specific villain being held inside.
When the Breakout happened, all of the prisoners escaped. Iron Man attempted to stop them but was beaten by a trio of villains holding a grudge on him. As they tried to kill him, Iron Man was saved by Hawkeye who also escaped from the Vault attempting to clear his name.
With no choice, Iron Man then hacked the systems and set it on self-destruct, ultimately destroying The Vault. It is unknown if all the villains survived or died in the blast, but later in the series it is seen that many of the villains escaped in time. The Vault has 142 inmates along with the ones in the list below
- Baron Strucker (escaped)
- Grim Reaper (escaped)
- Crimson Dynamo (escaped)
- MODOK (escaped)
- Technovore (escaped)
- Mandarin (escaped)
- Chemistro (escaped)
- A.I.M. (escaped)
- Living Laser (escaped)
- Whiplash (escaped)
- Blizzard (escaped)
- Hawkeye (after being falsely accused of betraying S.H.I.E.L.D. by Black Widow) (escaped)
- Various Unnamed Vault villains (escaped)