Wow. What film are you watching? The only movement the head makes is a snap backwards and to the left, then he slumps towards Jackie.
Not true. His head initially goes forward for an instant. His chin then impacts his chest and can go no further forward at that point. Clearly visible looking at the film frame by frame.
Except now you’ll leap to: “Well, the film was tampered with!”
Then after that, something else, and after that.....
Right? :)