Instead of his music playing and him walking down to the ring as usual, I could see him coming from the crowd and RKOing Bryan out of nowhere just moments after Bryan wins the championship. That would certainly come off as heelish rather than the usual cash in since he wouldn't even be giving Bryan any time to prepare to wrestle another match. He could even pummel the tired and exhausted Bryan and beat him for much longer than he has to to get across the message that it's not just about winning the championship, but about humiliating Bryan. Maybe he could even have him pinned, only to lift up Bryan's shoulders before the third count, just to show everyone that he's having fun and that he's not finished with him yet. And then he finishes it off by punt kicking him into oblivion for the pin fall. (Or maybe he just lets Bryan slowly stumble to his feet on spaghetti legs and then RKOs him one final time for the victory, and then punt kicks him after the match.)
At least if they want the audience to accept Orton as a heel through this cash in, that's the way to do it.
