Section 8.1: Outside the Sabakuma Tunnels
Make your way back to the Port Atlantis Teleporter.

Use the Teleporter to travel to Half Moon Cove.

When you arrive at Half Moon Cove, speak to Foreman Sanders. He will give you 0.70 PED in Universal Ammo and ask you to recover a Detectonator.

Navigate to the waypoint and retrieve the abandoned Detectonator.

Operate the Detectonator to pick it up. Kill eight of the Sabakumas. Then bring the Detectonator back to Sanders.

Sanders will reward you with some Anatomy skill and 2 PED in Universal Ammo.
Section 8.2: Inside the Sabakuma Tunnels
He will then ask you to enter the nearby tunnels and fight the Broodmother inside.

Travel to and enter the tunnels indicated by the waypoint.

Kill the Broodmother, then exit the tunnels and return to Forman Sanders.

Foreman Sanders will reward you with 0.50 PED in Universal Ammo and ask you to speak to Technician Larchi.