Unless Crooks was armed with a rifle equipped with a scope then it is likely he had a handler that made sure he was in the right place at the right time while the actual shooter’s kill shot was foiled by divine intervention.
The fact the police and Secret Service did not respond to reports of an armed man on the roof would support the theory if in fact “Crooks” did not have a scoped rifle.
Come to think of it— haven’t yet seen a evidence photo of the rifle he used, whatever has been genericized by creative writing. Scope on it- what caliber. All pretty screwy. They came right out with the carbine oswald used—bolt action. So they get by with “semi-automatic” AR “style” rifle. WTH?