Tangos patrol some of them. Finally, you needn't get all your operatives out of the dam. After you've gotten Kunst out and disarmed the bombs, the mission ends. Blue Team Blue Team is the best team to control. Its job is to get down to the detonator as quickly as possible, and to clear a path for the teams that follow.
All teams begin in the tunnel to the dam.
Approach the dam carefully. To the right of the tunnel entrance is a small concrete building with a stairway down to the water. Atop the building is a tango. Take him out, as well as another tango at a distance. The door to the stairway is locked, so you'll have to pick it.