I would like to build a dungeon that serves to muddy the plot line and the heading of the party in the campaign that I am running. A kind of mega-dungeon meant to get the party lost inside, or going somewhere the party did not intend to end up, like in the middle of nowhere when they were sure the BBG was at the end of the dungeon but he is not and the way out is confusing at best.
Is there a simple way to accomplish this without throwing the party into panic mode? Shifting walls and random teleporters will not work, because the party will be sent into high alert. I'm looking for subtle ways to get the party hopelessly lost without them knowing about it early on in the dungeon.