Felix wanders around the housing complex without any aim or purpose. As long... he isn't in an empty house, even a dark building full of strangers is better than that.
So he walks around, nearly everyone is asleep and those that are not have their doors closed.
Felix feels he shouldn't focus so much in his purposeless suffering, when every single so here has to face a world where they're copies of people. He feels bad for even comparing the two sufferings.
But he is so tired and sleep is not actually rest for his head.