MCRP 12-10B.1, page 200

Figure A-48. Clearing a T-Shaped Hallway f. Both shooters clear their immediate areas along their respective walls, starting from the nearest respective corner and continuing to the farthest respective corner (Figure A-49). g. Both shooters establish dominant positions that give them control of the hallway and the doorways leading into hallways. The covering team can then be called forward to provide security while the clearing team clears one end of the hallway and associated rooms. The clearing team then clears the other end of the hallway. Figure A-49. Clearing a T-Shaped Hallway (Continued) 25. Clearing a Stairwell. After entering a building, the assault element may encounter stairwells. The following procedures are used: a. Shooter Number One leads upstairs, one step ahead of Shooter Number Two (Figure A-50). Upon reaching the point just before he/she can be engaged from above, Shooter Number One turns around and covers overhead. From this point, Shooter Number One ascends the stairs, moving backward while covering behind and above. Military Operations on Urbanized Terrain A - 39