How do you hide on the ledge on the stasis map on gears of war 2?

The other night I was playing warzone on multiplayer and a member of the opposing team was hiding on the ledge at the end of the map above the stairs to get to the second level. (not the stairs in the center of the map). I asked the player how to do it but he wasn't giving it up. Help please lol. My GT is DrMrsth3monarch. If you know how to do it help me out thnx :3