As he ran, Li Yang was trembling with mixed excitement—nice excitement because of the cassiterite pebble he'd found, not-so-nice excitement because of the spear that had been thrown at him. After he'd been running for a while he stumbled and fell, cutting and bruising his knee, and dropping the spear. There was dirt mixed into the wound and Li Yang was hit by a wave of horror when he thought that it might become infected. There was no medical assistance in the New World! No ambulance would come racing around to save his life if he was close to death!
By the time he reached the camp he and Jake were trying to turn into a proper settlement, he managed to calm down. It was already common knowledge that the New World was miraculously free of diseases. Sadly, it didn't do much for the life expectancy of the colonists, who died in droves from hunger, exposure, and sheer stupidity.
