[masraum]

The OP isn't really an irrational fear, although he may be more fixated on it than most, but for good reason.

I know that there are folks that are afraid of bridges or high places because they are afraid of throwing themselves off despite not being suicidal. I think I've heard one of my family talking about the same weird fear.

Even as a kid, I was afraid to get into a fist fight because I was afraid that I'd kill the other person even though I am not a violent person and I have no secret desire to kill anyone and didn't torture animals (other than the odd ant via magnifying glass).