Yeah…Susan Twist played Isaac Newton’s maid in “Wild Blue Yonder,” the woman requesting a song at the bar in “The Church on Ruby Road,” one of the recorded station crew members in “Space Babies,” the tea server in “The Devil’s Chord,” and now the ambulance.
There’s no obvious connection between any of these, and in two of them, she didn’t interact with the Doctor or Ruby in any way. It’s curious.