This is a glitch that requires no Lag switch and is merely for fun. Normally you can walk into a box and it breaks. Now if you find a ledge with a box near it you can walk off that ledge and fall onto the box. Though this adds nothing like immortality or infinite ammo its fun to see listen to your friends comments on the Headset when they come to you and see you in a box stacked up. Just a fun little glitch.