Locate Kargail at the top end of the path leading up the mountain side directly from the docks. ( 380, 193, 514 ) /waypoint 380, 193, 514
When he stops running, hail him to kill him
Use the crawler hatchling from your inventory on his corpse.
Once it stops moving around, pick up (right-click > Pick up) the hatchling.
Multiple questers can release their hatchlings at once for the update.
[Note: Kargail will only spawn when you have the quest. If you do not see him immediately, run a short distance down the path and back up again to trigger him. Once spawned, he will run slowly from the top of the path towards the mountain wall to the right.]
Return to Maertha Pulzer.
Release the hatchling:
Return to the entrance of the Mortartoe Mines
Release (right-click > Release) the crawler hatchling from your inventory.
[Note: The hatchling will not release if you are too far inside the mines; stand just outside the entrance to release it.]
Return to Maertha Pulzer to complete the quest and claim your reward.