After Harry had given the lecture, while he was descending from the podium, however, one of the research assistants intercepted him, and began to ask him a question on the theory of relativity.... one that involved a lot of complex calculations and equations. Harry replied to the assistant “The answer to this question is very simple! In fact, it’s so simple, that I am going to let my chauffeur answer it!”
Why is it not will let as the decision was taken when he was replying, he did not make any plan before answering?
Is going to used to say that the chauffeur is going to answer right now?