Guard 1 (The Deadly Assassin)
From Tardis Wiki, the free Doctor Who reference
A guard was a member of the Chancellery Guard in the Time Lord citadel. When the Fourth Doctor arrived in the citadel and was being pursued by guards, he stopped at a elevator, which opened and revealed the guard. He then held the Doctor at gunpoint and started to move him down the corridor, before being shot and killed by the Decayed Master. (TV: The Deadly Assassin)
Behind the scenes
Pat Gorman clearly plays the guard again in part two, although Hilred said he was killed in part one.