: The sentinels guided the oblong across the dock and down to another
: unfinished structure still being shaped as they watched. Constructor
: machines like spiders spun hardening cocoons of metal around slowly
: ascending frameworks. Then Riser understood. From below the rock and sand
: out of the Ark's deepest foundation, a massive tomb was being prepared. A
: void had already been cleared to receive the coffin. Sentinels dragged it
: to the edge of the void, a strange grave at a place where there was no
: real dirt, no real planet, and latched into the waiting frame. The oblong
: coffin's blue lines flowed outward spreading into the confining struts.
: Riser puffed out his cheeks and looked up at his tall companion.
: Bornstellar was observing the ceremony with a grey, grim face. Hard to
: read. All Forerunner fighters looked grey and grim to the Florian.
: ------------When all was ready, Bornstellar raised his arms to address the
: tomb. "Ancilla 05032 of the designation Mendicant Bias, you have
: colluded with the greatest enemy of the Mantle." A deep voice issued
: from the coffin and was amplified across the platform, echoing from the
: ship, the dock, the tomb, even now being given its final touches,
: The voice
: now echoed off far bluffs and canyons, "Judge themselves, judge
: themselves..."
: "A sin to fight a sin," said Bornsteallar, "a lesser evil to
: fight a greater one. That is the choice I was forced to make, you had no
: such excuse, you brought matters to this point."
:
: "You are brought here to be sentenced. You have not been immediately
: destroyed because you may yet be needed. Your intinmate knowledge of the
: Flood makes you valuable should they return, but we can never trust you,
: never again allow you any latitude. You will be entombed here. Your
: processes locked, frozen into a single thought for all eternity:
: absolution. Should you be needed you will be reawakened, should there be
: no need you will be buried here until the end of living time."
:
: Bornstellar shook his head, "I wish only for the Mantle to be upheld"

Is there any hint at all as to why, let alone how, that became one of the Gravemind's go-to phrases? or did MB borrow it from the GM? in which case... well, WTF does it mean, or rather what does it mean when the Gravemind uses it?