Here is an Example.

If you want to do it with just 1 mirror hollow out a cube(using 1 postive Cube and a negative that is a little smaller and they you pull it out just before it comes out entire and then group them together(make Sure they have the same glass and reflectiveness) you can also have it surround the entire scene and make it a glass mirror with 100% Reflectiveness. You can also use multiple cylinders or cubes to do this as well here are the examples they are not brilliant just an example. this is the mesh view