This was a case of crypto-amnesia. The transmissibility of an illusion by one person to one or more other persons who are emotionally cohesive, is well established.
13 seconds sound clip from the Dead of Night (1945) movie soundboard.
You can hear this line at 00:52:45.768 in the Blu-ray version of the movie.
Quote context
[...]
- I'm not accustomed to solving complex problems with the careless ease of your brain's trust.
- It sounds to me as though you're completely stumped this time.
- Joan saw the room in the mirror as well as Peter.
- The witness I couldn't supply you with.
- Very well. You asked for it.
- I'm totally at sea. You wouldn't like to start again very slowly, in words of one syllable?
- Well, I'm like Grainger. I'm going to act on the warning. I'm going to leave here now, this instant.
[...]
