The King of the Beggars

Oliver Reed suffered a concussion during the filming of his death scene, and Roger Moore recounted in his book that Reed was supposed to be lying dead on the floor as Moore went into his closing narration, but Moore heard noises and initially thought Reed was attempting to play a joke on him before looking down and seeing that Reed's tongue was hanging out and changing colors, at which point Moore immediately dropped down to assist him and demanded that someone summon the studio nurse, and Reed survived the incident and returned to the series for another guest appearance.

@5:35 When Simon and Joe Catelli are fighting, Oliver Reed starts falling backwards well before he is supposedly struck, with Roger's fist coming nowhere near him anyway.