He suspected that the Second Doctor and his companions Jamie McCrimmon and Victoria Waterfield were from a rival archaeological expedition. He was working in the projection room when Kaftan locked Victoria in the revitalising chamber and went to fetch the Doctor to free her.
When Peter Haydon was killed, he was terrified and thought they should all leave the planet. When the expedition explored the cavern and Eric Klieg freed the Cybermen, Viner tried to put them back in their tombs. He was shot and killed by Klieg. (TV: The Tomb of the Cybermen)