S9E1: Fatal Transmission

In 1996, at Quincy Regional Airport in Illinois, United Express Flight 5925, a Beechcraft 1900 twin turboprop, collided on landing with another Beechcraft, a private King Air, that was taking off from an intersecting runway. Why did the fiery collision turn to tragedy, causing all twelve on board the 1900 and two on board the King Air, to perish when they were unable to escape the burning aircraft?