Iceland is a liminal place. People who normally never get lost find their internal compass suddenly on the fritz. They find themselves lost in thought and wander off, inexplicably drawn into caves and toward water.
While visiting Dimmuborgir, a few of us decided to visit this cave. As I climbed the steps, I found myself drifting further and further away. Upon arriving at the mouth of the cave, I found myself drawn toward the back and began to walk forward. My companions had to coax me back. Dazed, I arrived at the top of the steps and realized I was not myself. Thankfully, by the time I reached the bottom, I was once again grounded in the present and able to orient myself.
These sort of experiences are not at all uncommon in Iceland, which is why you need to keep your wits about you and not wander off alone.