After handing over the Colt and completing the “Surplus” sidequest, talk to Miya again to start this sidequest. She will then start a repeatable quest which will require you to bring her some blades. This is similar to Houston and Chimamanda's repeatable quest.
Talk to Dr. Kessler
to start this sidequest. You have to wait until you can explore The Tunnels
before you can proceed with this. Once inside the tunnels, wait until you get the objective to replace the fuse. Follow the path around and make your way to the generator room. The door is barred there so you have to find a different route. Jump on the nearby crates and generator to reach the upper part of the room. Jump through the hole and kill the walker on the floor. Grab the fuse and remove the blockade from the door. Replace the fuse in the power box to restore the power in the tunnel.
Exit the generator room and follow the hall. The door that's previously shut due to the lack of power should now be open. Open it and take the ladder down. It is pitch black down here so use your flashlight and flares alternately. Kill the zombies and take a sample from the glowing toxic waste ahead. Next, follow the tunnel to the left to reach a dead-end with the remains of a horribly mutated monster. Grab a sample as well to update Dr. Kessler
Continue to the radar dome and take the stairs to the left. Follow the walkway to the end to reach a room with consoles. The notes are found there.