urm...this even more evil and sick cheese requires a save game and possibly multiple reloads to get it to work right, but if you do this correctly, this is even more evil than using acid arrows to disrupt his spell casting...
you pass by the room where jon is on the way up to the level where you meet lonk the sane...the door is next to the stair well, and it is locked...you can pick the lock, and this is where it gets tricky...save the game, and open the door...now if jon sees you, he casts a spell called wish, (not the kind your party uses) that kills your entire party instantly, but if you can avoid being seen by him, you toss in about 6 cloudkills, or a few incindiary clouds, and close the door...he will take mondo damage, but he wont be killed due to his minhp item...but he will be reduced to one hit point...once the area effect spells have worn off, move the party to the next floor, and talk to lonk...when you are transported downstairs to meet jon, he takes one hit, and teleports out...because a while back you've damaged him so heavily he is almost dead when you have your big confrontation...
