I know about as much as you. I was on the right side of the VIP rail that was perpendicular to the stage, and so the guy was about 5-10 feet behind me. It happened about 15 minutes before the show was scheduled to start. People were calling for medics for about 2 or 3 minutes before anyone showed up. Once they did, they had to request backup because the guy was so large. Because it was behind me I didn't see much more. The seizure seemed to stop pretty quickly, he "came to" but was instructed to stay on the ground, and (I think) was eventually evacuated on a stretcher. Their set started on time.