Key Component

 is a Quest in Escape from Tarkov.

Dialogue
"I've reviewed the documents you've collected. Sanitar sends his men to every medical facility in Tarkov looking for certain components. But some of the substances are now only found in combat drugs. During our brief time working together, Sanitar mentioned that he had once intentionally written off a batch of these stimulants when he worked for TerraGroup. There are two places where this shipment could be now: the Laboratory or the Lighthouse, near the water treatment plant. The USEC Rogues could have taken the drugs to the second location if they found them first. I think you already realize how necessary these components are at this time. We need to finalize the cure as soon as possible. Procure me a shipment of these combat drugs."

Objectives

 * Locate and obtain the decommissioned stimulants on Lighthouse or The Lab
 * Hand over the stimulants

Rewards
"I received the components you found, thank you. I'm surprised that TerraGroup has missed the illegal write-off of such medications. Now let's talk business: after receiving the shipment, I immediately started working on the antidote. Eventually, I got the first samples ready. I've tested them on volunteers, the side effects are negligible. Here you go, you deserve it. The antidote takes quite a while to clear out of your system, so you'll be immune to the infection. But I advise you to stay out of the danger zone. I can use the leftovers to synthesize combat stimulants. You'll only have to pay for the supplies, and I won't charge you a penny for the work. Think of it as payment for your help."
 * +17,400 EXP
 * Therapist Rep +0.05
 * 1× Injector case
 * 1× Antitoxin
 * Unlocks barter for eTG-change regenerative stimulant injector at Therapist LL1
 * Unlocks barter for Meldonin injector at Therapist LL1
 * Unlocks barter for SJ6 TGLabs combat stimulant injector at Therapist LL1

Guide
In this quest you have to find a case with decommissioned stimulants on Lighthouse or The Lab. You must get the case on either location and hand it over to Therapist.

Lighthouse Water treatment plant location
Underneath a metal shelf inside the western electrical operation shack. 

The Lab location
Next to the door of the laboratory block (G22) on the second floor. 

Élément clé