The Nazir was an individual who desired greater closeness with G-d. He would restrict himself from drinking any grape by-product, and allow his hair to grow. He looked different and acted different. The Nazir represented a discipline of life and aspirations which raises him who has voluntarily vowed to adopt it above and beyond his contemporaries of belonging exclusively to G-d. Like the Kohain, he was prohibited from coming in contact with the dead.
Death represents the opposite of moral freedom and choice.
Once we have died we can no longer exercise the one quality that sets us apart and above all other creations, our free will. The Nazir represents the highest expression of free will, he who chooses to belong exclusively to G-d. The Kohain is designated as a symbol of a person who belongs exclusively to G-d. Therefore, both the Nazir and the Kohain must avoid coming in contact with the dead. Therefore, anyone who comes in contact with the dead must leave the inner camp.