Worker was called to repair the #2 Kiln Preheat Thermocouple which made it necessary for him to remove it from the Kiln. He detached the springs holding the Thermocouple inside the Kiln and when he reached to remove it, the Thermocouple suddenly ejected. Worker went to grab it before it fell out and grabbed the hot part of the Thermocouple that was inside the Kiln.