"Open Security Door" is an objective in the story mission Where Angels Fear to Tread.
Walkthrough[edit]
As the Vault Hunter descends into Control Core Angel, Angel explains some things. Once down there go along the corridor to the button. Hit it and go on through. You will finally meet Angel. She explains you need to steal and key and destroy the Catalyst: her. Head on through the door and into the next room. It is time for another battle.
Dialogue[edit]
Angel: "Eridium alone could never charge the Vault Key. It needs a catalyst - something to awaken its power. It needs... a Siren. Jack acquired his Siren catalyst a long time ago. He kept her hidden from the world for years, but finally - you will be able to set her free."
Angel: "I detect you're getting closer. Hurry and reach me - you must get the Vault Key and... deal with me. "
Angel: Executing phase shift. The key is here, but--"
Angel: To truly stop Jack from waking the Warrior, you cannot just steal the Vault Key - you must destroy his catalyst. You must destroy ... me. Jack's spent years pumping me full of Eridium, using me to charge his Key and manipulate his enemies. Destroying the Eridium injectors that keep me... alive... will stop the Key from charging. And it will end a lifetime of servitude. Now--"
Handsome Jack: "You get the hell away from my daughter!"
Angel: "Aghh!"
Handsome Jack: "What the hell are you doing, Angel?!"
Angel: "Stopping you, you piece of shit!"
Handsome Jack: "Rrgh - language!"
