Lt. Harris mission can't be completed

Release the Arachnos Prisoners from Lt. Harris leads to an empty area.
The Arachnos Prisoners, and presumably their captors, do not spawn there, and there is no door to enter.

The mission tab also does not have the information for this specific mission in the short series in it, as if the quest hasn't really advanced to this point even though it is directing me to it.


Edit:
Well, today they finally appeared. Maybe it just needed me to relog.