All throughout the movie whenever Colter (the main character) is talking to his handlers we always see it from his perspective and something you notice early on is how unresponsive they are to his tone and his emotions. He could be screaming or crying or in pain and they never seem to react to any of it.
Then towards the end of the movie we finally see the screen his handler's have been staring at the whole time and it's just a simple text readout of the things he's been saying.
I loved that moment because it plays off the audience's expectations and how we've been assuming, just as Colter had, that they could hear him even though, knowing what we know at the end of the film (ie. brain in a vat), that it would be incredibly unlikely.
It sort of re-contextualizes all of their previous interactions up to that point. They always seemed so cold and distant in their responses because to them he was just a line of plain text with no face or voice, was kind of chilling.