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double post, but:

http://nikon.bungie.org/gameplay/halo2_leg_walk/arbiter.html
http://nikon.bungie.org/gameplay/halo2_leg_walk/oracle.html

It's for the xbox but it does show that you can empty...

I believe it also works between Outskirts/Metropolis (Legendary only, since you only encounter sword-carrying Elites on Outskirts at that difficulty).

I'm not sure if it works between Sacred...