Carter (The Hand of Fear)

Dr Carter was a pathologist who was given the hand of Eldrad to examine after Sarah Jane Smith was brought to the hospital where he worked.

Biography
Carter and the Fourth Doctor examined readings from an electron microscope that showed the hand was absorbing radiation.

Sarah came into his lab, used Eldrad's ring to render Carter unconscious and took the hand. When he came to, he reported the theft and discovered he'd been unconscious for over an hour. Carter drove the Doctor to Nunton Experimental Complex in pursuit of Sarah.

The use of the ring on Carter brought him under Eldrad's influence — in Sarah's words, he had "seen the light of Kastria". In an attempt to prevent the Doctor from reaching Sarah, Carter attacked him, but his own momentum saw him fall several storeys down inside the complex to his death. (TV: The Hand of Fear)