Gommen

 was a criminal in the Last Great Time War. He posed as studio executive creating filmed and hired Nyssa as a stuntment but hypnotised her. He was as a medical Doctor and was using the machine to experiment of coma patients and invited people. Nyssa traced him due to his negligent and traumatising experiments. K9 Mark II gathered the evidence needed to put him on trial. (AUDIO: The Stuntman)