Sgt Shlyachin was a part of Stingray 1 crew during Operation Fairway. The aircraft crash landed in the Helipad, which is surrounded by a mine field. He initially survived the crash; unfortunately he tripped over a mine. Therefore his body is found in the middle of the mine field. This character does not have any significance to the story, even though he is directly mentioned every now and then by other Stalkers, when asked if they've seen any soldiers. Sometimes they will reply about Stingray 1 and say that one of the soldiers blew up on the mines.
His body is the only one found in the premises of this Stingray.