1. The Cuban government likely changed its mind about refugees for both practical and diplomatic reasons. Welcoming refugees would strain Cuba's already limited resources and cause more difficulties, while denying them allows Cuba to appease the U.S. government.
2. "Fidel Castro had Ivan's blood all over him." This quote has a double meaning referring either to Castro literally having Ivan's blood on him from killing him, or metaphorically having Ivan's death on his conscience due to the consequences of Castro's policies and authority.
3. When Mahmoud woke to find a pistol pointed at them, panic and fear likely flooded his mind. He would worry for his own safety and the safety of others in the cab, wondering if the driver intends to harm or threaten them. Mahmoud may think they are being carjacked, hijacked or taken hostage, and his heart would probably race with uncertainty about the driver's intentions and how the situation might unfold.