Clearly any special level should not have special features like anthills, beehives, pits or vaults.

Qui - maybe the gate is under a pile of rocks or a corpse or something? Have you been killing the ants in the "rooms" (the areas clear of rocks)? I recall dropping a shard on the gate (before I figured out what I was supposed to do to use them on it) and it showed up as a ' instead of an &.