Flooded Metro (exterior)

 shows up on the Pip Boy World Map in two places:


 * The Flooded Metro marker north of Arlington Cemetery (shortly Southwest of Anchorage Memorial) is blocked by debris when going down the entrance ramp, but a door on the right takes you through offices and then maintenance tunnels which come out on tracks next to some stairs which go up to the Arlington Cemetery.


 * The Flooded Metro near the Southern border of the map is West of Arlington Library (halfway to the Nuka-Cola Plant) and across the street (North) from a raider camp. This metro is mainly caved in, and is a maze of utility tunnels and shafts filled with Mirelurks of all types. Heavy firepower may be necessary. It also has a very high complex of stairs leading downwards, breaking into small rooms near the beginning. Be warned that there is a shaft in the middle of this complex; resist the temptation to jump the railing, it's a long fall.

Notable Loot

 * When entering from the South (not Mason District South), following the tunnel up right, the first room has a Guns and Bullets behind a transformer, near a skeletal corpse. In the same spot is also a Scoped .44 Magnum and some ammunition.
 * A Pulowski Chamber outside the metro near the South entrance (not Mason District South) contains a Chinese Army: Special Ops Training Manual.
 * Tumblers Today and Pugilism Illustrated in the Raider camp southeast of the southern entrance. Also a Nuka-Cola Quantum.
 * Near a shaft close to the Mason District, through a tunnel to the East, is a booby-trapped chamber (A). On a barrel in this chamber is The Shocker with instructions. The chamber contains some other weapons and ammo as well as a Nuka-Cola Quantum.
 * In an egg chamber down a staircase-lined square pit, ankle-deep in water, there is a gun case with a random weapon (Laser Rifle and Microfusion Cells, etc).

Bugs

 * The lower level of the Flooded Metro filled with Mirelurks has been known to glitch heavily on the Xbox 360 version, literally causing them to rise up through the floor at random. It is unknown what causes this, but for example, if a Mirelurk is below you, the Mirelurk will sometimes (especially if it is attempting to get by a barrier) suddenly appear on the level that the Lone Wanderer is on.  This can happen frequently.
 * Doorways can become impassable, perhaps due to objects on lower floors clipping through the floor and obstructing your path. If this happens, try saving the game, plant a Frag Mine or two (conveniently, there are several available in the Flooded Metro), and shoot them from a safe distance. (Bug encountered on Xbox 360.)
 * PS3 - Buggy Mirelurk locations. They may disappear only to reappear elsewhere, which seems similar to the bug above because it has been observed mainly in stairwell locations. The Mirelurks seem to drop one or more levels then climb back up using the best possible path.
 * 360 - The Shocker was found on a Mirelurk Hunter corpse