It could have simply been the screenwriters way of injecting some more human avarice into the film. You're about to kill a guy, so why not cause him further torment during his last few moments of life by causing him to think that his padrone had turned on him. Like Woltz, I don't think it was an ab-lib. But if it were and it did not fit the scene, FFC could always have reshot it.
"Generosity. That was my first mistake." "Experience must be our only guide; reason may mislead us." "Instagram is Twitter for people who can't read."
