The Marseillaise scene from Casablanca - especially as it was in 1942 and no one knew the outcome. Many of the actors were refugees themselves including Madeleine Lebeau who herself had fled France. You can see what it means to here when she sings.
There's also the end of the Dambusters. Barnes Wallis asks Gibson if he is going to bed. He says that he has some letters to write. In real life, Richard Todd who played Gibson, was a decorated officer in the Parachute regiment and took part in the attack on Pegasus Bridge. He would have known what it was to write letters to families about their loved ones.