MCRP 12-10B.1, page 176

c. Before entering, Marines throw a hand grenade into the new entrance to reinforce the effects of the original blast. When making a new entrance in a building, they consider the effects of the blast on the building and adjacent buildings. If there is the possibility of a fire in an adjacent building, Marines coordinate with adjacent units and obtain permission before starting the operation. In wooden-framed buildings, the blast may cause the building to collapse. In stone, brick, or cement buildings, supporting fires are aimed at the corner of the building or at weak points in the building construction. Figure A-25. Lower Level Entry Techniques Military Operations on Urbanized Terrain A - 21 THE-TWO MARINE LIFT, SUPPORTED 1 TWO MARINES STAND FACING ONE ANOTHER, HOLDING A SUPPORT (A BOARD OR BAR). 2 ANOTHER MARINE STEPS ONTO THE SUPPORT. 3 ONCE BOTH FEET ARE ON THE SUPPORT, THE TWO MARINES RAISE IT, LIFTING THE THIRD MARINE UPWARD AND INTO THE ENTRANCE. THE-TWO MARINE LIFT WITH HEELS RAISED 1 ONE MARINE STANDING WITH PALMS FLAT AGAINST THE BUILDING, FEET OUT FROM THE BUILDING ABOUT 2 FEET WITH HEELS RAISED, IS LIFTED BY TWO MARINES. 2 3 TWO MARINES BEND OVER FACING EACH OTHER. THEY EACH GRASP A HEEL OF THE THIRD MARINE AND WITH ONE QUICK MOVE LIFT HIM/HER UP AND INTO THE ENTRANCE.