The group is talking about normal group things: where to go next, who ordered the wrong drink, why the music sounds like a speaker is dying.
Then she drops in a line that is technically public but aimed too cleanly at him. “Some men pretend not to notice anything.” Or, “I almost wore the other dress.” Or a question that only makes sense because of something he said ten minutes ago.
The table keeps moving, but the sentence narrows. Sometimes her friend hears it and goes quiet for half a second. That tiny silence says plenty.