Ive had a similar experience years back, we were at a disused quarry, me and a few mates trying to ride some of the jumps and steep hills, when a guy on an alu orange (i think it was) came steaming down a steep one, through the bottom of the quarry and up the other side which stopped about four feet higher than the level of the ground behind it, so was the 'jump' of choice for those that went there.
He superman'd off his bike as it went wrong midflight, and landed chin first on a massive stump of a long since snapped young tree, tore his chin open side to side and down to the bone
We rushed over to find him getting up and dusting himself off, holding his jaw, then he pulled his hand away and blood was gushing from his wound and his hand was soaked in it, he simply said, 'ahh shit, thats me off to hospital then' and got his bike up to ride off, bars were squiffy, rear wheel and i beleive one of the chainstays were both bent, he got on and wobbled off, we asked if he wanted us to go with him and he just said 'nah ill be fine, happens all the time' LOL!
Although it did play on my mind we shouldve follwed as he was bleeding profusely, and i always envisioned him falling off and passing out through bloodloss and bleeding out on the trail between the quarry and the next village!