Wherever you go, your mind will go with you. Your knowledge will go with you, your prejudices will go with you, your scriptures will go with you. Your idea that you are a Hindu or a Mohammedan will go with you. So what are you renouncing?
Zen says: be empty. Look without any idea. Look into the nature of things but with no idea, with no prejudice, with no presupposition.
A sannyasin is one who has no prejudices, who has not chosen any ideology to be his own, who is choicelessly aware of all that is. In this choicelessness you will be in the middle. The moment you choose, you choose some extreme. The moment you choose, you choose against something; otherwise there is no question of choice. Being in a choiceless awareness is another meaning of being in the middle.