What is significant about the tragic irony displayed in placing Soraya’s phone call and Amir’s terrible discovery back to back at the end of the chapter?

Tragic or dramatic irony implieds that we knew Sohrab would attempt to kill himself if he had to return to the orphanage to wait for his papers. Perhaps the reader knows this. It makes sense that Sohrab would rather kill himself than go to the orphanage. Returning to the orphanage especially after taking out Assef's eye, would be a fate worse than death.