Its not only a very old counter-sniper technique, its a combat proven one. Vasily Zaitsev the highly decorated Soviet sniper from the battle of Stalingrad in WW2 succesfully used this technique to locate and netralize Germany’s alledged “Super-Sniper”. It is however very possible that this is a staged picture but I wouldn’t refute it solely on the presence or lack there of the soldier’s body armor or other equipment as it is incredibly hard to crawl and sneak in all that equipment. It could be that he shucked it upon entering the building. But the camera man felt comfortable enough to stand up and snap a “hoo-ah” little pic so once again it could be staged…