Hard to tell, but it looks like Dan stumbled over a board on the ground, but the way he went down suggests he was knocked out prior to the fall. However, when he went down the first time he fell back awkwardly the same way. Looks like he's just not very coordinated when it comes to falling down, as most people aren't. It's heartbreaking to hear his head hit the ground and see him laying there like that. I don't think any of the skaters deserve to be jailed seeing how it was an unfortunate chain of events, but Dela definitely seems like the instigator that started it all. Good to see the filmer extend a hand to help him up after the first fall and suggest calling an ambulance after the second.