MCRP 12-10B.1, page 164

b. The most common mistake Marines make when passing a basement window is not being aware of it. A Marine should not walk or run past a basement window because he/she presents a good target to an enemy gunner inside the building. When using the correct procedure for negotiating a basement window, the Marine stays close to the wall of the building and steps or jumps past the window without exposing his/her legs (Figure A10-B). c. An alternate method is for the point person to pie off the window (or other opening) as he/she approaches it. As the point person moves toward the window, the second Marine (behind the point person) steps out to provide security to the direct front. The point person continues to cover the opening by pieing, all the while using the near edge for cover. The point person covers and sectors off that part of the interior that can be viewed from the outside. The second Marine moves with the point person and maintains security to the front, eventually moving past the point person as the point person clears the inside corners of the opening. Once the opening is cleared, the second Marine may assume the duties of point, or when subsequent Marines move up to secure the opening, the original point person may reassume those duties. Figure A-11 illustrates this alternate method. Figure A-10B. Marine Passing Basement Windows 7. Use of Doorways. Doorways should not be used as entrances or exits because they are normally covered by enemy fire. If a Marine must use a doorway as an exit, he/she should move quickly through it to his/her next position, staying as low as possible to avoid silhouetting himself/herself (Figure A-12). Preselection of positions, speed, a low silhouette, and the use of covering fires should be emphasized when exiting doorways. Military Operations on Urbanized Terrain A - 9