In Writing with Hitchcock (2001), Steven DeRosa noted that Hitchcock supervised them through every draft, asking that they tell the story visually. He told Roger Ebert in 1969: Once the screenplay is finished, I'd just as soon not make the film at all.
A drop kick is a type of kick in various codes of football. It involves a player dropping the ball and then kicking it when it bounces off the ground.
With the drop kick however, in contrast to the volley, the ball touches the ground during the shot. With a volley, the ball is never hit 100% at the optimal moment in time, with the dropkick even smaller fractions of a second will determine success or failure.