Verisimilitude is a big word for a fun time. Few people want guro to happen in real life, but sometimes it probably does happen. We can make guro more realistic by imagining situations that might be plausible in real life.

Obviously it would be too easy to just imagine a crazy serial killer. Such killers surely exist, but using one takes away all the challenge and creativity. It is better to suppose that no one is deliberately engineering the guro situation, and see how we can plausibly explain the guro situation still happening.

For example, a car runs off the road and crashes into a tree. The tree breaks and some branches smash through the windshield to stab the people in the front seats. There's no end to the realistic possibilities for branches randomly stabbing people.