There is no such thing as a single most crucial question in the PI of IIM Kozhikode, or any other B-school for that matter. Some things you must not compromise on our understanding of your topic of study and fundamental GK; you must know your profile like the back of your hand. The most essential thing is to keep your cool when you don't know the answer to a question or two; a lack of confidence will cost you far more than not knowing the answer to a question or two.