Guide (The Chase)
A guide attended to tourists at New York City's Empire State Building's 86th-floor outdoor observation deck, and pointed out various landmarks to be seen.
Among his guests one day in 1966 was Alabama native Morton Dill. The guide led his group around to another side of the deck, although Dill remained behind to gaze at the scenery. They returned to find Dill pounding on the deck and loudly rambling about "a trick". The guide went to summon a policeman, asking a large man to watch Dill in his absence and try to keep Dill from committing suicide.
The guide had narrowly missed the brief appearances of the Doctor's TARDIS, the First Doctor, Ian Chesterton, Barbara Wright, Vicki Pallister, a Dalek time machine, and a blue-bumped Dalek. (TV: The Chase)