When I first saw this shot, I thought there was a thick fog in the room. I thought this because when Niko shoots his rifle here, the light from the gun glows around him. Well, it glows because the camera angle here is shooting through a glass window. You don't know this until the next shot, though. Notice in the background in another room how a circuit breaker blows and sparks fly. A dead person is a few steps behind Niko. Also, just under Niko's left arm and behind the railing in the background seems to be a sewer grating with water flowing out. Do you see it?