How did external events beyond Kennedy and Kruschev’s control shape the outcome?

After watching the video, 3 Men Go To War, address the following: http://sockshare.net/watch/qvo89Z8x-cuban-missile-crisis-three-men-go-to-war/google.html
Does the individual matter in terms of outcomes? Why or why not? Would different leaders have resulted in a different outcome? 
What were the key areas of miscommunication for the Soviets and the U.S.?
What choices did each have available to them?
How did external events beyond Kennedy and Kruschev’s control shape the outcome?