As in the topic, the two nastiest elemental temples can be done without breaking a sweat by reading a scroll of monster aggravation, just after descending to either temple level.
Both Yulgash and Nuurag Varn teleport around the level freely and can be lured out of the their respective spots and dispatched easily in the very first room the PC descends to.
They can be killed without having to risk item destruction from lightning or traps and all the PP drainers, corrupting vapor rats, elementals, annihilators, chaos wizards and their summons etc. can be ignored.
I don't think that there was so much thought put into designing the layout to just let players circumvent it.

However, scrolls of monster aggravation are otherwise useless so I'm at a loss as to the validity of this bug. Maybe this is actually their sole purpose?
It still feels wrong to do the temples that way, I assume that the same could work in earth temple, but having *all* the wall-ignoring monsters attacking the player might not be such a good idea.