Doran was a Chlorian engineer. Lady Adrasta tasked him and Tollund with identifying the function of the Tythonian ship.
Doran wrote a paper in which he concluded that the ship was the remains of an old temple and most certainly not alive. The Fourth Doctor quickly disproved Doran's findings, after which Lady Adrasta had him thrown into Erato's pit. There, he died of fright. The Doctor discovered his body. (TV: The Creature from the Pit)