I assume that his ambush of the French was, like the killing of Franz Ferdinand, the spark that started an inevitable war, but that's just my gut feeling. I'm not terribly familiar with the background to the war.
My comparison was more about the effect of the killing, in sparking a massive war, rather than the motivations.
But anyway, what I read was that he wasn't actually supposed to ambush French soldiers, just demand they leave or surrender (though his orders were given by the local commander on his own, not from instructions from Britain), and try and capture them if they refused, killing them if necessary. But instead, being egged on by his Native American allies, he ambushed them.
I'm also aware that the exact events are contraversial, especially ab out whether the French commander was shot trying to negotiate peacefully or not, and different sources give different versions of events, which is why I'm asking.