Safety Deposit Box

Safety Deposit Box is an achievement/trophy $$

Requirements
The Courier must trap Father Elijah inside the Sierra Madre Vault during the quest Heist of the Centuries.

In order to do so, at least one of the following skills is required to be at 75:
 * Explosives, Science or Repair
 * Lockpick or Sneak
 * Barter or Speech

When speaking with Father Elijah on the terminal, chose either: "Unless you come down here, I'll destroy the vault, everything in it." Pass an Explosives, Science or Repair skill check. Pass a Lockpick or Sneak skill check. Pass a Speech or Barter skill check.
 * "Now that I'm here, are you coming down?"
 * "Then I'll find a way to unlock the secrets of this vault, take them for myself."
 * "I don't care about the vault, I just want to leave."

Then exit the Vault and reach the elevator while remaining undetected by Father Elijah, either by backtracking the long way, or by waiting until he approaches the Vault door and the blue laser grid is removed from the nearby doorway leading to the elevator.