You're probably looking for a personal experience of fear of death or injury like car wrecks, encounters with animals, etc. - and I've had a few of those - but my worst one involves my daughter when she was 8 years old. Anybody with kids will understand.
She wrecked on her bike near our house and bumped her head pretty good. After a trip to local doc-in-a-box who released her when she couldn't even stand or walk on her own, we did not feel comfortable and ended up taking her 30 minutes away to a larger hospital ER where they did a brain scan. Next think we know she's in a Med Flight helicopter to yet another hospital where a neurosurgeon was waiting.
There was a delay in the helicopter picking her up, so I was able to get the 3rd hospital ER in my car just as the chopper touched down. I watched as they wheeled my unresponsive daughter into a treatment room. I followed them into the room without thinking and no one stopped me. The neuro guy asked one of the flight nurses who I was, but he went back to work and didn't order me out. Guess he didn't have time to waste. I watched from 10 feet away as they intubated her, doctors and nurses scurrying around, looking at CT scans, etc. Within 5 minutes she was off to surgery.
After 3 tense hours in a waiting room, the neurosurgeon came out to tell us she had survived a subdural hematoma larger than a golf ball inside her 8-year-old skull. He said probably 15 minutes more and she would have been brain dead. The pressure on the brain stem was cutting off oxygen.
This is the same type injury that killed Liam Neeson's wife and also I think Formula One driver Michael Schumacher who was hurt skiing recently has a similar injury.
Anyway, she's 21 now and a beautiful, smart and perfectly normal young woman, albeit with titanium plates and screws in her skull. But just recounting that story brings back the fear and dread we felt watching all that unfold with my daughter's life in the balance.
P.S. Yes, after getting scolded by the neurosurgeon, we bought all the kids bike helmets.