#165326
(1) Fast travel to "Forest Camp" Base Camp, in Soviet Installation.
(2) Go to the central structure. There are 4 enemies camping in the right side of the building.
(3) There are 2 enemies patrolling around the rocks southeast of the first group of enemies (they may be northeast sometimes). They may attack you while you are fighting the first group, but they'll still count as a separate encounter.
(4) Go to the Copper Mills entrance, where you'll find 4 more enemies.
(5) Go to "Copper Mills Yard" Base Camp and fast travel to "Forest Camp" again. Repeat the process.
Sometimes, the third group of enemies doesn't spawn, but it will be there in your next "lap". With this method, you'll obtain the achievement in around 10 minutes.
#165326