How to stop rendering

You could use a script to disable a camera's Camera compoent, like this (in javascript):

 var cameraObject : Camera;
 function disableCamera()
 {
      cameraObject.GetComponent(Camera).enabled = false;
 }

EDIT: As @Statement commented below, I already have a camera, so there is no need to call GetComponent().

 var cameraObject : Camera;
 function disableCamera()
 {
      cameraObject.enabled = false;
 }