How do I train myself to be able to stand gory things?

The career I want to go into involves being able to withstand gory and disturbing things. I can barely get through a saw movie. How do I train myself ? I wanna be able to see something and forget about it, I just don't know how. When I ask my friends who love gory things they say " its not real ", but when I watch them I feel like its my pain and its real, and disgusting!