IRL, I was about 10 and I saw some fucking nasty roadkill - a squirrel, with its stomach squashed and split open and all of its little innards spraying out of its body, including a little kidney and little guts. I've never seen any horrible human violence or carnage (other than on movies) - I've never seen someone getting a headstamping or anything - but it has happened to people I know.
That nasty bit of roadkill is perhaps the nastiest thing I've ever seen in real life, although I studied it quite a bit and wasn't that grossed out.