After I dealt with an early childhood phobia of mummies (by gradually desensitizing myself to them--I still get an adrenaline surge when I see one out of its coffin and unwrapped, but I can deal with it) I've ben afraid of very little.
There are the defensive reactions; if I was being bullied and in danger of getting beaten up I'd cower and cover my face just like anyone else would. And there are the startle reactions; if a car honks at me or there's a sudden loud noise or something I don't expect, I jump and get an adrenaline rush. And there is still some "spook factor" associated with dead bodies in general, though I know logically that there is nothing a dead body can do (except spread disease) that could hurt me.
However, I don't have illogical fears; if I see a horror movie, I generally wonder at the stupidity of the characters. They generally panic and ignore simple rules of what someone should do when in danger: Stay together, think clearly, call the police. But they don't think clearly; they scream, run around like ninnies, and get themselves killed by whatever monster or curse that's coming after them.
I have not been in very many real-life dangerous situations, other than the bullying and a car accident that happened when I was nine. My mother was going about 30 mph on a newly resurfaced gravel road; and we skidded off the road and flipped over onto the roof of the car.
I found myself hanging upside down from the car's seat belt; and my mother was in complete shock. I thought to myself, "Hmm, we've had an accident; I'm not hurt; Mom seems fine too." So I told Mom, "Come on, let's get out of here," and we crawled out through the windows (which were fortunately open).
I didn't cry or make any sort of fuss; as it later turned out I had actually been injured, gotten a rather bad bump on the head which would have been a concussion if I'd hit my head harder (or was a very mild one). My mother came away with no injuries at all, except those we both got from crawling through brambles on our way out of the car.
I also did not panic when I was thrown out of the house at age 8 by an annoyed stepfather; I walked around the neighborhood, dressed in pajamas and socks, for two hours before my mother found me and brought me back home.
Running away from home at age 14, after my stepfather threatened to kill me, was also accomplished with more logical action than fear; I walked the five miles to my grandmother's house, where I stayed until my stepfather calmed down.
Maybe we Aspies "aren't afraid when we ought to be"; but this also means that, if we are good at thinking clearly and logically (as we usually are), we can handle dangerous situations better than our NT counterparts. A golden mean would be to have both the strength, speed, and endurance that adrenaline gives, but also to be able to think clearly... I imagine this is what paramedics, police officers, and other emergency personnel learn to do.