It is not unreasonable for him to be startled and upset that he is being disturbed from what he thinks is a peaceful walk.
Once he notices he was about to walk off the cliff and assuming he does not want to die, can you imagine that he wouldn't fall down on his knees and turn towards his "savior"?
Back to your question:
Let's assume that God ordained that we "irresistably draw men away from cliffs" (preaching the gospel) as a way of saving that man.
The man is still responsible for walking off the cliff, however, would you want to face God with the knowledge that you failed to utilize his ordained method of saving people from walking off cliffs?
Jean