You'll be screwed if it asks you to write a radio transcript involving three characters you make up that offer different readings of your text.
Just understand your concepts so thoroughly that you are able to be flexible with it. Besides, there is really no doubt that the amount of practice essays you do, you'll remember what point flows best after what.
You will be marked on how well you understand the given medium. If they ask for a feature article and you give them an essay, they will mark you down for it. As well as this, your arguments and reasoning must address the question. This is all well and good for journeys, but things like critical responses, they're quite particular. Like others have said, you don't know the question yet.