It is often made explicit, or is implicit, that the Hero has no choice but to go forward:
In Dances with Wolves (1990), once John Dunbar reaches Fort Hayes, the "foulest man he has ever met" leaves with the horse and cart. There is no way back.
In The Matrix (1999), Neo has a choice between the red and blue pills. Once the choice is made, he cannot return (later, it is made explicit that there is "no way back").
In Gladiator (2000), once Commodus has murdered Maximus' family, there is no path but forward.
-------------------------------------------------------------------------
LEARN MORE AT: http://www.clickok.co.uk/index4.html
-------------------------------------------------------------------------