Things don't turn out so well for Jon Favreau's character Happy Hogan in this slightly different version of his meeting with an Extremis-powered henchman in Iron Man 3. In fact, the third installment of the Iron Man franchise could have proved fatal to Happy.
These storyboards, drawn by Daniel Sweetman, are very similar to the final scene. But the biggest difference comes with these words in reference to Happy: "...closes his eyes and dies." In this version, he doesn't pass out; he doesn't appear to die. He dies.
It's not clear from the storyboards alone how strong a possibility Happy's death was, but it looks like it was at least considered. If Happy had died, it certainly would have added some heat to Tony's anti-Mandarin rage.