Doesn't that tell you that Hickey firing the rifle is something that never happened. Hill would have heard the firing of the rifle even after he had jumped off. Hill is a two shot witness.
Hill heard Oswald's shot-1 & shot-2.
It is strange that Hill did not hear Hickey's autoburst of at least 4 shots.
Hill had no reason to lie. After all, Hill hearing a 3rd shot would simply support an Oswald shot-3.
But Hill was hitting the tarmac at Hickey's first shot at say Z300, & was galloping during the following shots (at least 3 ovem), & was level with the left front wheel of Queen Mary at Z312 (Hickey's last shot).
So, praps Hill truly did not hear Hickey's shots.
Greer & Kellerman mentioned a flurry of shots i think 20 times in their WC testimony.