Lockout gravity lift trick
From Halopedia, the Halo wiki
The Lockout Gravity Lift Trick is where one player goes to the top floor of the "Lift Tower" and jumps right down the hole circumventing the gravity lift at the very front (closest to center area). The lift will be reversed in operation, and instead of levitating one, rapidly propelling one down its depth.
One can also do this by jumping straight at the diagonal top it throws you straight down making it easier than either messing up or slowly getting to the very front of the lift.