Sabina was once taken to a gathering of other Czech émigrés. They were all standing around talking about how the right thing to do was fight back against the Russians. Sabina tells them that they ought to go back and take up arms.
This leads to some finger pointing against Sabina. Who is she to talk? She didn't oppose the Russians; all she did was paint.
Sabina listens to a grey-haired man talking and knows that all he cares about is everyone else's political profile, not how good they are at whatever they do for a living.
Because Sabina is a painter, she has an eye for detail. She knows this type of man – there are others like him, and they all have long index fingers they use to point at other people. She tells the grey-haired man he looks like President Novotny and then leaves the gathering.
Sabina wonders what binds her to the other Czech émigrés. "The only things that [hold] them together," she decides, are "their defeats and the reproaches they address to one another" (3.4.9).
She realizes she's not being fair; there are many other émigrés who, unlike the grey-haired man, are not finger-pointers. But remember that Sabina is attracted by betrayal. By resenting the other émigrés, she is betraying her country.
Sooner or later, her string of betrayals will have to come to an end.
Sabina gets onto a train where she meets Franz for their trip to Amsterdam. She wants to tell him to make her his slave, but she is too reserved to do this.