How long will somebody stay a live after being ripped in half if they don't receive any medical help?

I'm writing a story and I need to know if you immediately die if you're ripped apart or if you live for only a few seconds after wards. I'm talking about internal organs hanging out ripped in half. Super gory. I need the answer pretty quick though, so please answer! Oh, and if you're going to guess please make it educated and based on fact. Thanks!