Why a Reverse Valve Body?

Drove in a mustang with a reverse manual.VB. Guy runs it through 2nd and goes into 3rd..BANG! Something pops and he tries to get it into neutral but he has to ratchet it back through 2nd and 1st to get N. And that loaded up the motor every time. He went back to N321 the next day with N and R lock out. YMMV