Is that in the final third of the film, Chris Evans’ character Curtis tells us a story about his past.
It could have easily been shown in flashback. In fact, most movies/scripts would have considered that moment tailor-made for a cutaway to flashback, de-aged their cast and let that moment play out, acted out for the audience.
But instead, it’s just Chris Evans’ face, lit in such a way that it starts to become a face we stop fully recognizing.
It’s just Chris Evans’ performance.
And it’s important that we see/hear him tell this story. Because as he tells this story we see how this story affects him in the now. This character has to be allowed to tell this story, with his face, with his voice.
About the only thing I feel like I can immediately compare it to on-screen is Anne Hathaway singing “I Dreamed a Dream” in Les Mis a few years ago, and it is equally devastating.