Instead of waiting around for so long in custom games, boot up FORGE MODE.
Load up Halo 2 in Forge mode and go to Warlord (NOT Warlock Anniversary)
Once in the map, fly to the centre pillar in edit mode.
Look directly at the object in the middle and press

to open Object Options.
Scroll down to Spawn Time and change it to 1 second.
Next, click Advanced. At the very bottom make MIN count and MAX count both 1.
Jump back into play mode and go collect the object.
Once it has been collected 5 times, this pops right away.