Isn’t that the point fear of the unknown??  seriously your chances of getting killed are slim as they have only beeen 15 deaths since 1923 (I can’t remember the exact date right this second)  Bodily injury the percentage goes up.  The number of gorings increase as the crowds size increases.  When I firsat went back in 1999 there were 3 gorings for the whole fiesta and that was thought to be high.  in the last few years there can be 3 people gored in one run.
 
Know what you are doing before you get into the street, knowledge is your best friend in pamplona and luck.  I personally know 3 people that have been gored.  and one that was trampeled very critically.  a LOT OF IT IS BEING IN THE WRONG PLACE AT THE WRONG TIME.  You need to fear the other runners more than the bulls.  There are a lot of bad cases of road rash, sprained this or that,an occasional broken bone or stitches.  A lot of people are treated in the streets right after the run that don’t make the injury lists.
 
I could go on and on about the bull run but I won’t bore you.