This is a simple one. What you have to do is conspire with the doctors and a group of your friends. If and when she wakes from the coma, you'll want to stage her hospital room to look like the depths of Hell. Get a few devil outfits from your local overpriced costume shop or, if that won't work, some S&M gear. The best way to emulate the look and feel of the eternal flames of Hell is to light stuff on fire, so definitely go with that. When she wakes, be dressed as Satan and shout "WELCOME TO HELL, I AM YOUR GOD NOW." The look on her face will be priceless and will endear for many years as a wonderful memory. Good times.