How about this: Leave everything about reaping exactly as it is, except -- if the vote being cast would be the one that triggers reapage, and the user casting it is a janitor, then make the number of 'keep' votes necessary to inhibit reaping higher, like 4 or 6, instead of the normal 2.
The effect would be that a janitor can cause the reaping of a node even if the consideration has enough keeps (2, or even 3) to prevent reapage normally.
But reapage would still be prevented if there were a greater critical mass of 'keep's.
I reckon we are the only monastery ever to have a dungeon stuffed with 16
,000 zombies.