Anyone who has participated in sports can tell you that there are unwritten rules. In auto racing, backmarkers let the frontrunners pass. In baseball, you don't bean the opposing team's star player. And you never run up the score on a game that you have in the bag.
So you can bet your ass that if your soccer team is up by 5 goals with ten minutes left in the game and you're still sending your striker on a run into the box, if I'm playing keeper I will come out and drop him. I might swing at the ball with one hand, but then my shoulder is going into his chest. And if he takes a while to get back up, while then that's your own fault.
Note: ref awarded me the free kick on the play as well, called the striker for a dangerous play.