Professor Boston Schooner was the chief curator of the Deimos Moonbase museum and the self-described "leading authority on the history of the Ice Warriors". He spent "[his] whole career" studying the Ice Warriors.
Professor Schooner was shocked to see there were Ice Warriors that had survived after, according to him, being "extinct for hundreds of years". He thought they were "the last of their species" and "unique". Schooner sabotaged the atmospheric re-ioniser, stopping Supervisor Finch from killing them before they could reach the base, framing Tamsin Drew for the act.
When the Ice Warriors took over, Professor Schooner suggested to turn up the heating of the base to slow them down. Instead of this, he turned the heating down and tried to learn about them more closely and "come face to face with the past". The Ice Warriors refused to accept his help, though Professor Schooner showed them the atmospheric re-ioniser. The Eighth Doctor arrived and passed Professor Schooner the sonic screwdriver to sabotage the re-ioniser so that the Ice Warriors couldn't use it to kill the 300,000 human colonists on Mars. Professor Schooner bought time for the Doctor as he escaped to the landing bay, and the Ice Warriors killed Professor Schooner for betraying them. (AUDIO: Deimos)