hobgoblins in hip waders
This is a story about D&D. That fact should tell you exactly where the phylactery is going, without a doubt -- the dungeon.If you look closely, the phylactery looks like it's heading for the ocean. And Xykon is actually better off with it at the bottom of the ocean - since it's indestructible, nothing can happen to it down there, and his enemies will never find it. He should just leave it where it is.
OotS is a story. Do you get angry when the book you're reading continues page after page, chapter after chapter? How about comic books that continue the story for years on end?
I don't know, it seemed fine to me. It's a moderate victory in the middle of the story, pulled off by one PC and an NPC. Frankly, considering how badly this scene started out for V, this is practically a miracle.
It would have been just as anticlimactic for the phylactery to fall into the rift, and for Xykon to look at it and go, "Crap. Now I have to make a new one." Which was basically the only other option.
Or did you actually think the main villain of the entire comic was going to be destroyed right now?