When Caje throws a grenade at the German machine gunners, it lands in a pile of leaves, several feet short of the Germans. Then there is a huge explosion that sends the Germans in the gun emplacement flying, but none of the sandbags around them are affected.
The squad find out the hard way that the field has land mines in it. But they don't think about the possibility of anything else being booby trapped as they look for souvenirs in the bombed out building.