It's obvious to me that JFK had already been struck by Z228.
Unless, of course, he was in the process of loosening his tie, or something.
-- MWT 
'Unless, of course, he was in the process of loosening his tie, or something'Difficult, since there was a piece missing

Thomas, I opened the original vid in QuickTime 10 on my iMac desktop. Note the timeline bar which appears. Using my cursor while selecting the small vertical bar, I was able to toggle the video back-and-forth from slo-mo to medium to high speed and everywhere in between.
My conclusion: Martin Hinrichs is a naughty boy.
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I suggest that interested parties try this for themselves..