If you are participating in an apparition event and enter in a cellar, when you leave the cellar the event is gone. You can see the event mark but the place is empty, no mobs, no players and no event at all.
If you are participating in an apparition event and enter in a cellar, when you leave the cellar the event is gone. You can see the event mark but the place is empty, no mobs, no players and no event at all.