I believe I do have a timeline of events that you might find elucidative.
Newt is teaching his class about Plato and Aristotle.
He explains that Aristotle was wrong to claim that heavy things fall faster than lighter things. He uses a short poem to remind them of this:
Whether they’re large or whether they’re small,
Has no effect on the rate which things fall.
But whether you choose to accept this or not-le,
Depends on your faith in that fool, Aristotle.
He asks one of his students, Spencer, who it was that proved Aristotle wrong in 1592. Spencer, who had not been listening, incorrectly guesses Plato. The answer was Galileo.
Spencer explains that the SOE communicates with field agents using “poem codes”. The message sender and recipient encrypt their messages based on an agreed upon passage of text. For security, this text must be carried in the agent’s head, but not be something well known generally.
The passages need to be intensely memorable, unpredictable and, ideally, consist of twenty-six words.
Spencer recalled the rhymes that Newt used to teach him in class as memory aids, and thought that Newt could help with this. He tells him that suitable passages were in great demand.
At 3:30am, Newt is watching television in the common room of the school at which he teaches. He is with two students from his Physics class and one other teacher.
They are watching coverage of the moon landing, which is due to take place within the next half hour, when they are discovered by an irate senior teacher, Mrs. Mill.
Newt asks to speak to Mrs. Mill outside the room. Once outside, she insists that they stop watching and asks Newt if he plans to defy her authority in front of the students. He says that he would not do that, but he thought he might very quietly defy it out here.
A stranger with a foreign accent approaches Newt and addresses him as Mr. Nightingale. Newt asks if he had taught the man years ago.
The man tells him they have never met, but that he had always wanted to meet him. He then recites this short poem:
I had a walrus for a pet.
Why I bought it, I forget.
I fed it kedgeree and rusks,
And used best Blanco on his tusks.
From the style of the rhyme, Newt recognises it as something written by himself or Jerry. He remarks that animals and kings were their speciality.
Newt is gratified to hear that the man had remembered the verse for all these years and that it had “worked”.
Russ learns Newt’s name, which leads to a discussion of amphibians and, in particular, why turtles are not amphibians. Newt gives him a brief scientific explanation of the difference between reptiles and amphibians, but Russ does not want to hear more.
Instead, Russ asks Newt for a story about Teenage Mutant Hero Turtles. Having been informed that the turtles names are Michelangelo, Raphael, Donatello and Leonardo, Newt tells Russ a story about turtles in Renaissance Florence.
In the poem, Jerry tells the audience of the years he spent living with Newt during the war. It was there that Jerry first started writing rhymes, for which Newt would pay him a ha’penny each (on condition that they scan).
He praises Newt as a teacher, storyteller and friend, before concluding with the lines:
Well, since you ask me for a toast…
O Nightingale! O Uncle Newt!