Talk to Mechanic about the EMP blast

Pure trader screen — no raid required. Open Mechanic's tab and trigger the dialogue. Mechanic is the resident TerraGroup-skeptic among the traders and immediately suspects the EMP wasn't an accident. He sends you to Streets of Tarkov to recover a fragment of the device that caused it. Make sure your trader rep with Mechanic isn't blocked by an unfinished previous chapter — Tour gates Mechanic, so finish Tour's Factory step first if the dialogue won't appear. After this chat, queue up Streets with one of the two keys ready.