It appeared that he just whacked the back of his head really really hard on the ground. The IV was probably because scalp lacerations tend to bleed an awful lot would be my guess. Unfortunately I've been there and kinda remember fighting with the EMT treating me because I was so dazed I had no idea my melon was split, much less why some strange dude wanted to stick a needle in me. I certainly hope he makes it through with minimal effects from the blraon trauma.