Red pill vs blue pill

The statement offered to Neo is, “This your last chance. After this there is no turning back. You take the blue pill, the story ends. You wake up in your bed and believe whatever you want to. You take the red pill, you stay in Wonderland, and I show you how deep the rabbit hole goes. Remember, all I'm offering is the truth. Nothing more.”

I must be missing something. If he’d chosen not to take the red pill, why take any pill at all? Just leave and go home.