Locksmith! - 25G
You will need to open all the doors in the map, you will most likely get this if you do the "Der Electrician" acheivement as to get to the teleporters you need to open all doors.
As there are other routes to each teleporter (as in you don't have to open the first doors from where you start to get to all of them)
if the acheivement hasn't unlocked look around the map for a door you may have missed, the last door I opened was on the left side of the pack a punch machine. You may do this too.
Thanks to Kung Fu Riki for this...
There are two debris, three doors leading to a teleporter, and four regular doors.
Door leading to a Teleporter: 1250