My uncle was a WW2 RAF pilot. He was shot down over enemy-occupied France. Rescued by the Resistance, but then betrayed by one of them.
We have a photograph of him walking around in Paris, before his arrest, with Nazi officers in the background.
He was taken to Buchenwald which, thankfully, he survived. When he finally came home, he sat up all night with his father, talking about his experiences, but then after that said he wouldn’t talk about it any more.
Some years later, he was called to give evidence against the person who had betrayed him, who was sentenced to death.