Fix K-9

Navarro Base
Raul, the vertibird mechanic, has the motivator that needs K-9 to get back to operative mode. Doctor Schreber removed K-9's ability to move when, during the experiments, K-9 disapproved of the doctor's sadistic methods and bit him. This information can be obtained from Cookie (the base cook), the doctor, or K-9 itself. One of the lockers in the vertibird hangar contains the required motor.

Navarro Sub-floor 1
The laboratory room is soundproof, so you can close the door and kill the sadistic doctor. Now you can talk with the cybernetic dog, and use the part on it to get it fully functional.

Note: This is the only NPC that can roam the base with you without wearing a Power Armor. He can also help you in combat with the deathclaw, if you so chose to go rampaging.

Rewards

 * Kill Dr. Schreber: 1000 xp
 * Repair K9: 3500 xp

Reference
Cameo: K-9 is the name of a robotic dog The Doctor from the Doctor Who series used to possess. With it both Fallout 1 and Fallout 2 have a Doctor Who reference, being the one in the original Fallout an special encounter where you actually find The Doctor's blue Police Box/Time-Space Travelling Vehicle, the Tardis.