The game is somewhat misleading about the location of the lever that can be used to disengage the vault brakes. The mission clues state that "A level which can be used to decouple the vault's breaking mechanism is being kept in the vault maintenance room at Dolores Michaels' Deposit & Loan Bank" and searching the "Vault Maintenance" room on the 2nd floor "Security & Admin" reveals no lever at all. In fact, the lever is to be found in the attic (up the shaft from the third floor), right where the clue is found, within a drawer next to the only desk to be found on the level.

Interestingly, another misleading statement is the main character going on about how loud crashing the vault will be, and in spite of the fact that the best paying contract during the mission "The Bank Run" states that the player should not wake anyone up, namely the "Quiet as a Mouse" contract, crashing the vault seems to be the best option that will not make the player fail the "Quiet as a Mouse" contract. By comparison, accessing the vault from the "Vault Control" room and moving the vault either to the director's office or to the archives on the bottom level, is an action that will wake up the entire bank, leaving the player to have to dodge all the guards to the vault.

Reading the lore on various sheets of paper sprawled out across the mission "The Bank Job" reveals some information about one of the security people that devised a code that when entered would pop all the safes within the vault open at the same time. Later on, there is another piece of information that gets added to the "Mission Clues", that reads "The sequence 0, 1, 1, 2, 3, 5, 8, 13 appears to have something to do with the safes inside the vault. Keep these numbers in mind if you want to crack the code."

Looking at the code, this seems to be the Fibonacci sequence (sequence A000045), and it can be spelled out longer than the mission clue provides:

	0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 

Here is an ASCII floorplan where the plus signs and numbers represent safes, with one of the safes marked as "dagger", from where the dagger is retrieved:

          dagger
  3 +-----+
 2 +       + 5
  1 +     + 6
       ^
       |
       | entrance

The code has to be entered clockwise, starting from the left-most safe (1) when entering the vault after unlocking it and then ending with the last safe (6) on the right after entering the vault There is an additional problem here because one of the safes does not have a combination lock; the one that the main questline opens using the vault keys in order to retrieve the dagger, and for that safe, the numbers in the Fibonacci sequence have to be skipped. Additionally, numbers that exceed one single digit, simply overflow onto the next safe tumbler.

Here is a table with the safe numbers, marked clockwise starting from the left after entering the left, corresponding to the Fibonacci numbers that have to be entered:

With all the numbers entered, all the safes will just pop open, excluding the safe that holds the dagger and that must be opened using the mission keys.