We all have asked ourselves, after the last beheading, how could a person calmly kneel there - read a long anti-American statement and then have your head cut off when you know what's coming? Any sane person would be fighting till the last breathe. If you could you would get up and run, even though you would be shot - which would be much preferable over the alternative. The question has inspired conspiracy Nuts to come up with all kind of strange angles, with the most bizarre I heard, that it was a CIA video with special effects to make it look real - all to get us into a war to feed the evil "military industrial complex".
The answer could be quite simple, and I heard this on the radio from a former CIA operative. The event has been carried out dozens of times, with the execution cut short and you returned to your cell. Each time you are told to read the statement, and then taken back, with no execution. After a dozen or more times of you doing this, and your statement sounding less and less forced, and you expecting this day would end back in your cell, you just kneel there.