What does it feel like to know, with total certainty, that you have less than a minute left to live?

Fyodor Dostoevsky found out on the morning of December 22, 1849. Twenty-eight years old, standing in a white burial shirt on the frozen parade ground of Semyonovsky Square, he watched the first three men in his group get tied to the posts ahead of him. He was sixth in line. He later wrote his brother that "no more than a minute was left me to live." Then, as the rifles came up, a messenger rode in waving a reprieve. The execution had been staged from the start, arranged the day before by the Tsar himself, built purely to break the prisoners through terror before commuting their sentences to hard labor in Siberia.