I think the reasoning for shooting into the water was to scare the bear enough to stop its charge.. the loud noise accompanied by the people in the boat pry were enough to stop the bear.. think of the flipside, if he would have shot the bear, that bear would not have instantly dropped, and now the bear is in survival mode and will fight to its death.. The smart choice was probably to scare it away, not shoot it and piss it off even more..