Gamer has been removed
Select the mission "all ghillied up" and walk forward until you encounter 2 enemies (right at the start of the mission). Wait until you hit a checkpoint and then alert those enemies (or throw a grenade at the white building with enemies inside).
They will alert reinforcements with 3 dogs. Knife them (snapping their neck does not count) and kill yourself by throwing a grenade to the floor and walking over it.
Repeat until you unlock the achievement.