If you are in deep space, and there is an infinite plane mirror, and in front of it there is another infinite mirror that is two way, with the see through side towards you, what do you see? Is it the image the universe behind you?
Two way mirrors are just very reflective windows. If both sides are equally bright, both sides can see the opposite side as clearly as their own reflection. If one side is much darker, then there is the illusion that light is only transmitting one way. In fact, light transmits both ways, but light transmitted from the darker side is so low it is not visible on the brighter side because on this side, self reflection is just too bright. This is analogous to not being able to see through your own window at night when the lighting in your room/office is higher than out in the street. People in the street can still see what's happening in your room very clearly.
If you are in deep space, you will see your reflection and all the stars behind you in the mirror setup, and possibly multiple ghost reflections also as light bounces inside the mirror cavity. If there are stars inside the cavity, they will shine through easily since the light coming from behind you isn't much greater.