Donahue's dedication to science and mathematics creates a convincing theory and I make no argument against save for one thing. I own an AR15 in .223 caliber and have fired it many times. It is piercingly loud. I have fired it without having my hearing protection in place and it is painful. Your ears ring for hours afterward. If Hickey did in fact fire that rifle from the back seat, the front passengers and agents on the running boards would have been very noticeably startled and temporarily and painfully deafened by their proximity to the muzzle. I've not seen that undeniable fact addressed in the book or any other discussion of this theory.