I caught up with Stephen Amell at a special event for 'Arrow' and 'The Flash's' two-hour/two-night crossover to talk about Barry and Oliver's big fight (the episode is called "The Flash vs. Arrow" after all!) and what that does to their relationship after the crossover, as well as what's the focal point of Oliver's mindset right now, and what Katie Cassidy will bring to the Black Canary.