I've always found that
thinking about gruesome things is far, far, worse than actually seeing them.
Sometimes, when thinking or talking about a specific injury, I get wigged out and feel worried that I couldn't handle it in real life. That has yet to happen.
I think part of it is this: when I
imagine an injury, I always end up picturing, not what it would look like, but what it would be like to personally suffer that injury. That's a bit much.
When I
see a wound, it's something I can be more objective about. It's over there, it's on that person, I can see what needs to be done, and I are too busy doing things to sit there imagining the actual injurious event. Or rather, there is no need to imagine it, because I can frakking see it. That's not to say that I lose all ability to empathize with the person over how it must hurt, but I am able to separate myself from it.
This is just me, of course. I don't know how others react. But I'm better off witnessing an injury than reading about it.