I don't believe I talked to Taimi, or I may have talked to her before everyone else loaded. The brief instance was completed and I left it. The "Return to the surface step" is flagged as completed and greyed out. No further interactions or dialog are available or triggering. I likely tried to talk to them immediately after the loading screen back to gyala delve, but before other NPCs loaded.
Chul-Moo and other NPCs are currently standing around. Their presence appears to change on each map load. Sometimes they're all there, sometimes they're not. Usually seem to not show up if there's enough players around.