The original Rook Evolution door is missing a handle, so I made one taking inspiration from the Original Prusa Enclosure.

The handle attaches to the already existing panel connector at the back.
With the added thickness, a longer screw is required so you'll need to replace your existing one.

You'll need to use a ball end allen key to tighten the screws up, since access is a bit awkward.  

I used OpenSCAD with BOSL2 to model this.