hi,
here is a text tut for anyone strugling with this,
Steps,
1. Line up with the right edge of the stairs
2. slowly walk up the edge of the stairs, and move your cross-hairs inbetween the gap between the rock and the stairs
3. Walk forward till you hit the rock, while keeping your cross-hairs still.
4. You should be in the glitch! Be smart to test it with George or a crawler before re-starting a round!