Best way to farm tome?

[Heavens]

Do it at your own risk. I have seen mass perma-bans for doing less than this in other games.

Not seeing how this is an exploit. Mobs leash based on independent aggro tables by game design. Maybe the intention was the entire instance should be cleared, but this is no exploit as that's how every other mobs in the entire game functions. If they don't like it they can change it to add the entire party to the aggro table for dungeon/raids.

Worked like this in FFXI and they didn't care then. If anything it rewards parties that are more coordinated.