Sorry if the glitch name fooled you, this glitch actually just shows you how to get inside certain boxes in the map Evacuation.
How to do it...
All you have to do to get inside the boxes is get on the corner (of boxes in video), and crouch repeatedly (again and again) fast. If you get it right you will then fall through the corner of the box.
(It is the second glitch in video below, starts at 43 second mark)
