MCRP 12-10B.1, page 195

Figure A-39B. Shooters Clear Immediate Area f. Cross Method. When employing the cross method, two Marines position themselves on either side of the entryway. Each Marine faces into the room covering the corner of the room opposite his/her position. On a prearranged signal, each Marine alternately enters the room. Each Marine crosses quickly to the opposite corner while covering the half of the room toward which he/she is moving. Once in the near corner, he/she assumes an outboard kneeling position to reduce his/her silhouette and continues to maintain coverage of his/her half of the room. He/She may change the position of his/her weapon to best cover the room. (Figure A-40) Figure A-40. Cross Method of Entering and Clearing Rooms 21. Covering Team Members Used To Support Clearing of a Room a. Three Marines Clearing a Room. Clearing a room with three Marines involves the same procedures used by the aforementioned two-person clearing team, with a third Marine (from the covering team) following immediately (stacked) behind Shooters Number One and Two. Shooter Number Three moves to one side of the door and establishes a center sector of fire coverage (Figure A-41). The remaining covering team Marine provides outside security. If the split position is used, Shooters Number Two and Three are placed on the opposite side of the door. A - 34 MCWP 3-35.3