X-13: Attack of the Infiltrator!

X-13: Attack of the Infiltrator! is a main quest in the Fallout: New Vegas add-on Old World Blues. The Courier is tasked to find all the Stealth Suit Mk II individual suit components.

Upon completion, the Courier is awarded with the "Cardiac Arrest!" trophy/achievement. Part of this quest overlaps with the subsequent Project X-13 and the suit itself.

Detailed walkthrough

 * Enter the X-13 testing facility, located near the perimeter fence to the west of the Big MT dome.
 * From the entrance door, go through the reception area into the corridor ahead. (For reference, to the right is a small room sealed with a force field; entry is not required for this quest.)
 * Turn left and explore the rooms adjoining the corridor. The three parts of the Stealth Suit Mk II can be found here (boots, gloves, and chest plate), along with terminals detailing the development process.
 * Once all parts of the suit are assembled, continue along the corridor and open the door at the end, which leads the player character towards the testing area.
 * The Courier's objective is the door ahead, across the walkway spanning the large force field.
 * Accessing the nearby terminal with the Stealth Suit Mk II in the player's inventory will unlock the door, allowing entry to the testing area.
 * If the Courier is wearing the suit upon entry, it will comment on the test and direct the player's attention to the start area and test terminal below them. They can make their way down (via the stairs) through the doors ahead, or simply jump down into the room.
 * Activate the test terminal to start the basic infiltration test, in order to begin initializing the stealth suit.
 * The player can freely explore the entire area before beginning the test. A search of the walls and desks will reveal many (currently inert) laser tripwire emitters used in later (optional) tests. With a Science or Repair skill of 50 these can be permanently disabled or hacked (from a red laser beam to a blue, reading the Courier as friendly; no alarms will trigger when crossing the blue beams). One can also destroy the patrolling robots to make the trip easier.
 * Once the player begins the test, they must make their way through the area, avoiding any patrolling robobrains. If the Courier is detected, the test will reset and they must return to the test terminal to start again.
 * Find the administrator's office and retrieve the X-13 document from the wall safe. Doing so will complete the quest and shut down all security measures. A reward will appear in the safe next to the test terminal.
 * There are several routes through the area on the lower floor to reach the safe. Alternatively, the player can start the test then turn right from the test terminal and go upstairs to the observation level. The player can make their way to the area above the administrator's office and simply jump down to reach the safe, avoiding the security.
 * Once the Basic infiltration test is complete, the Stealth Suit Mk II will be upgraded (Sneak bonus increased by +10, to 25). Also note that enemy Robo-Scorpions will appear throughout the X-13 facility under the direction of Mobius.
 * Completing this quest will also continue Project X-13, allowing the player to further upgrade the Stealth Suit Mk II.