Huge Vault Door

The Huge Vault Door is a character in Portal 2. It is a huge metal door which blocks many places in the facility and escapes from test subjects whenever it gets defeated and opened. It is also willing to capture, experiment on or kill anyone when given a chance.

In the single player campaign, it is a minor antagonist which blocks Chell from entering the historical mines of Aperture Science and trying to rescue GLaDOS from the bird. Chell defeats it by quickly pressing 2 mechanical switches from different sides and the Vault runs away from her showing a small door with the tunnel to the history cave. It appears again and blocks Chell and GLaDOS from returning to the top facility this time. It is defeated again due to Chell flinging on a manual override and pushing an override switch which bumps the door to wall and hurts it a little but it survives.

In the Co-op campaign the Vault Door is the main antagonist. It is revealed by GLaDOS that the Vault Door had kidnapped thousands of human test subjects underground in its lair and murdered anyone who tried to kill it and rescue the humans with various weapons like turrets, death pits, crushers, a conveyor belt and death goo. During the course of the Co-op game, GLaDOS teaches Atlas and P-body various gimmicks which Chell uses and then at the last chambers of each of the 4 courses she sent them to retrieve useful sources of power and research in the following order: search cameras, the fortresses blueprints, an important override code and control of the full facility. With all the 4 sources collected, GLaDOS finds the location of the fortress and sends Atlas and P-body to navigate through multiple underground test chambers and then fight the Vault Door. When the Co-op robots reach the evil door, they gesture on front of its eyes, burning them severely and the Vault Door screams in pain and runs away from the robots. As usual it runs away and moves but doesn't manage to escape. Instead it permanently dies from the injuries to the eyes. It is then never seen again.

## Trivia

* The Huge Vault Door is one of the most evil characters in the Portal franchise due to its annoying and deadly nature. It is also one of the least appearing characters in the Portal series.
* In Co-op, despite being the main antagonist and being the arch-nemesis of GLaDOS and the Co-op robots, it doesn't appear in the game or have any significance in the story until the last set of levels in the game. That said, the Door had more intelligence and death obsession than both GLaDOS and Wheatley.
* The final boss battle of Co-op, which is against the Vault Door is very different to the GLaDOS and Wheatley battles. In both the other battles the player has to get cores and attach them to GLaDOS's body in 6 minutes. In the Vault Door boss fight, you have to activate both the blue and orange gels on the ramp on front of the door and gesture on front of it. Unlike the GLaDOS and Wheatley battles, there is no timer.
* It is unknown how the Vault Door originated or how it found thousands of humans and attempted to kill them. In fact, The Vault Door is the only Portal character whose backstory is completely unknown.
* It is unknown if The Vault Door and Wheatley had any relationship together.
* It is one of the 2 silent characters in the Portal series, the other being Chell.
* GLaDOS doesn't exactly address the Vault Door as a villain but still thinks of it as a threat.
* In comparison to the other main villains of the Portal franchise the Vault Door is different as while both GLaDOS and Wheatley start as sidekicks and then betray Chell eventually (GLaDOS does get redeemed in the 2nd game) the Vault Door is immediately a villain from its 1st appearance.
* GLaDOS talks about human facts with the Co-op robots more than anything else which some Portal players think foreshadows the Vault Door's plot but there aren't any hints revealing the Vault Door being the mastermind.