On my FeBe I planned to the Slime rune as my third. But when I got to Slime:5 and actually saw TRJ I got scared and left... I decided to to get the Abyssal rune but accidentally entered Pan instead. After dying twice in Pan and getting the Demonic rune I decided I had enough and left. Considering how difficult Zot would be I decided I might as well get the Silver rune too, since if I can't beat that then how could I beat Zot? I did that with the help of a lot of Trog summons and enslavement charges on low MR meatshields like ogres.

Zot itself I did with a lot of 1v1 berserk fights IIRC. I did get killed twice by OOFs, so make sure to stock up on extra lives before entering Zot!