Assuming an implementation in which Gehennom starts to get destroyed after you remove the Amulet: When you kill the high priest of Moloch, he gives you a multiline death message calling you a fool and saying you don’t know what you have done, and maybe hinting a little bit at why Hell is about to go to hell.

When you kill the high priest of Moloch, Moloch himself shows up with the Amulet, and you have to beat him up and take it from him.

Divine lightning (a god smiting you, particularly Moloch when you attack his high priest) should ignore reflection; it’s a “wide-angle” blast of lightning. Maybe this should apply to the lightning monster spell too. The high priest of Moloch should also be shock resistant.

The crossaligned high priests on Astral are hostile.