In the movie Atomic Blonde, most of the characters are spies for one nation or another, competing to get their hands on a list, hidden in a watch, that contains the identities of every spy in Berlin. The main character, Lorraine, arranges to smuggle the list's author, a Stasi agent called "Spyglass", to the west, with the help of her apparent partner in British Intelligence, who is called Percival. Spyglass has memorized the list and thus is a threat to multiple intelligence agencies, though
it is the Russians and the English who eventually murder him.
In fact, Percival acquires the list himself and discovers from it that
Lorraine, though supposedly a British agent herself, has other loyalties. She kills him to keep this secret.
If the list contains this information, and Spyglass has memorized it, why would he have trusted her?
He knew the Russians were trying to kill him, and that she was supposedly working for the Russians.