Since Ashitaka didn't want to hurt anyone by turning them into a pile of bugs, he hopped in his car and headed for the backroads, hoping there would be no one there (I'm assuming you've already figured out that this has long departed from the movie's actual plotline). Except, Ashitaka was a terrible driver, and ended up ditching his car on the side of the road.

He ended up finding a discount toy store, and went inside. Something there caught his attention. It was a handheld electronic Battleship game. He decided that he could just kill time playing the game until his curse went away. And so he did (in hindsight, however, the game looked more like Pac-man than Battleship. Oh well).