I cannot overstate how impossibly game-breaking this is.
Obviously, I'm a puny, weak man and I have decided to abuse this to no end, on every level possible, especially since I have a wand of destruction (and now I have 4 wands of destruction...).
Started with one RoDS, stack of ~20 arrows of slaying, ~20 potions of water, 9 scrolls of chaos resistance, 12 pots of ultra healing, 8 pots of gain attributes, etc.
Now multiply all that by 2, then multiply the result by 2 and again multiply by 2...
I'm not even done yet. It's a horrible and equally addictive exploit, needs to be fixed asap; I would change the priority to 1.