Zoning resets your progress, however, zoning after you finish the 11 kills does not. You are safe to move on to the Etched Rock.
A message informs you how many remain after each kill.
Many spawns can be found around (F-11).
It is best to avoid caster-type Alter egos, because Obstreperous Panopts frequently enter an "absorb-all-elements" stance, denoted by the Panopt's eye turning green, and Alter egos wielding elemental magic will constantly heal them.