Go to forge and select sandbox. When you are in the game press up on the d-pad, then press X, then go to equipment.

Go to trip mine, place on the ground and press X on the mine. Then a menu will pop up, press X again, go to run-time minimum and press A.

Then go to the number of mines that there is on the map, press B and press B again, now you pick up the mine and stay there and start tossing them.

Soon everything will go away and come back. Now you can go out on the sand without getting killed by the Gaurdians.

This cheat works once per round.