Vault Ambush!

Vault Ambush! is a short level 6 mission. When the player reaches level 6, they will receive a Vault Ticket which grants a visit to The Vault, along with a message from the Ambush Bug. The player must visit the vault, open all presents and exit to complete this mission.

Objective

 * Equip, then use your Vault Ticket to teleport to the Vault

Despite this official description, players are not required to consume the one-use Vault Ticket - they could simply access the Vault (multiple times) through the On Duty Menu, with different frequencies depending on game access.