Sometimes my friend will eat a twix, and he strips all of the chocolate and caramel off before eating the biscuit, so I can image how disturbing the scene must have been to watch.
You get over that quickly. I mean yeah, I sympathize with the prey--I know what it's like to be stalked by something, nearly defenseless, and know that there's a very good chance you're not making it out of there alive. I can't imagine what being mauled to death is like, but it can't be fun. At the same time, though, to act on that sympathy is to condemn the predator to starvation and an even more agonizing death (I know what starvation is like too). SOMEONE is going to die in a predator/prey scenario. For the predator to live, the prey must be killed. If the prey isn't killed, the predator dies. It's harsh and cruel, but it's the way nature works. Once you realize that, you can observe such scenes with a bit more objectivity; sure, it's gruseome to watch the prey get devoured, but at the same time the predator is usually one, maybe two meals from starvation himself, and desperate.