How to do it.
Go to the area above the cave entrance with a
warthog and grenades, there's a spot on the hill that the
warthog can climb, and to the left there's an area that looks flat,
but in-between there's a hillside that the warthog cant climb.
So have a person throw grenades at the gap to "push" your
warthog up the hill to an area where it can climb.
Now that you are there, you can go anywhere on
top. Here's the trick:
You will only freeze if you are in certain areas,
and only when the blue beam is released (approx. every 16
So you have sixteen seconds to go anywhere, and make
it to a "safe" zone before you are frozen by the blue beam.