Machinima Respawn's Crazy Filmmaker has detailed how to unlock three Achievements in Call of Duty: Black Ops 2's Mob of the Dead zombie map Alcatraz.
The goal here is to build an airplane and use it to flee the notorious island and make a break for the Golden Gate Bridge. The plane is made up of five parts which must be gathered and brought to the roof in order to be assembled. One piece lies in the room directly below the roof in a locked cage. To advance you'll then need to enter purgatory mode by heading to the top of the spiral staircase and shocking yourself.
Once you've done this, head back down the stairs taking note of the numbers you see on the way down and zapping the fuse boxes at the bottom of the stairs until the number on each matches what you've seen which will unlock another part of the plane. The third piece can be found down by the docks though you'll need two people to get to it. Enter purgatory mode once again and zap the box, revealling the plane piece.
Another piece can be found in the showers and once again you'll have to enter purgatory mode, zap the box in front of the laundery machine before fighting off a wave of zombies, once you've done this the machine will open and you can pick up another part of the plane.
While down at the docks you also need to enter the generator room in purgatory mode and zap the three generators. This unlocks the warden's room upstairs where you'll find the part.
When you finish builing the plane you'll unlock the 'No One Escapes Alive' Achievement for 75 points. Once on the bridge if you survive for an entire round after Round 15 you'll unlock another 30 point Achievement, the 'G G Bridge'. A third achievement, 'Making the Rounds' which is worth another 30 points is unlocked by completing the process listed above three times.
The second time the plane parts have been replaced by fuel containers, get to the Golden Gate Bridge a third time and your 30 points will unlock.
You can watch the video below.