Stuck on the LA Vault

[[S!C] ΞX Gloomwalker]

i am THIS close to being able to go head to head with The Master, but I've hit a brick wall. On level 3, there's a locked door leading to the lift which I just can't get into. My lockpick skill is crap, the computers don't do anything and nobody has a key. What do?

[cat in box says a lot]

that is the door to blow up the cathedral without facing the master, there should be a door on level three (i think it's on the bottom right corner) that leads to a hidden area where the master resides

[kud1]

The Master is located on level 3 in the Overseer's office. On level 4 there is a nuclear bomb that can be activated without confronting the Master.