Call of Duty: World at War

This event happens about halfway through the "Breaking Point" mission, right before Polonsky gets killed. Three Japanese soldiers will surrender which triggers a short cutscene. If you go behind the soldiers and point your camera right at one of them, it should be fairly easy to sweep an SMG over each of them and earn the achievement.

this happens when you get to the courtyard (in Okinawa) you get a little mini cut scene (you lower your guns) but stay back , you will see three enemies surrendering but they are really suicide bombers as soon as it lets you draw your gun shoot them all and save the sarg. then get ready for the last part of the level

I ran up to the Sarge as soon as the mission started then when you were allowed to use weapons I went kamikaze with grenade and took out the 3...I myself died but the achievement unlocked b/c the Sarge was safe.

The other guides did not help me as it wasn’t clear when this happened.
This scene happens near the end of the mission.

After coming out of the tunnels, by going up some stairs, you’ll now be inside a building.
Follow everyone up more stairs.
Sarge will break down a door and run left.
When you hear someone say “sarge, we have movement”
Those are the guys that will suicide themselves around sarge.
Two will grab sarge on the right and explode, one will grab the other guy on left and explode.
Be on the right side, looking at sarge, be ready, as when your weapon comes up and able to shoot,
Shoot the two on sarge, possibly try for the third.

If you don’t succeed, drop a grenade in your feet and reload the checkpoint,
Coming out of the tunnels.