There is no indication that these were made by the people here. If they were, then we'd need an explanation as to how some made their way as far away as Sa-Hareth.

But it is true indeed that the mirrors affect the dead as well as the living.

Now, do you really think there is more to be gained by staring at those shards? If not, I suggest going back to camp before noon and the waking up of the mermaids.