Hey guys and gals! Here is my 100% Achievement guide and full walkthrough for Infliction!
This is a story related Achievement.
But after you do a few things around the house, you will be able to enter your garage (the room on the left next to the front door).
Once there, turn left you should see a rug covering something.. take that off, press A to interact with the mirror and Achievement will unlock.
Go to 10:10 in my video to see where and how this unlocks.
Hope this helps!