Align the mirrors as shown in the picture, then stand underneath the middle mirror like in the picture. Shoot Envy's beam straight up and the door will open.

I spent along time trying to figure this out on my own but couldn't. After digging on the forums I found a link to somebodies Lets Play and got my answer. Thought people would like a simple way to quickly access the answer via steam so I made this.

Thanks go out to that guys video and for those interested his Lets Play is the link below.

https://www.youtube.com/playlist?list=PLuzuQWCPP75ozIiwRZofHpEbjKgNgInWq&feature=view_all