Before attempting to get this achievement, make sure you save. In order to get this achievement, you'll have to
*** Spoiler - click to reveal ***enter the D'ni linking book behind the fireplace without grabbing the missing page hidden within the switches. Once you teleport to D'ni, Atrus will chastise you for not bringing the page and proclaim you are both eternally stuck in D'ni. You will, however, unlock this achievement.