There is a famous expression which states "Write what you know". I guess the more experiences you have - both good and bad - the more able you are to put yourself in your characters shoes. Writing from experience puts you squarely within your comfort zone - you know what it looks like, how it sounds, and more importantly how it makes you feel. This is something you can transfer to your characters with a certain amount of ease. Research is a major part of writing, but there is something about having some personal knowledge of what your characters have been through, or are going through, that feels much more comfortable.
The single-most shocking incident in "Absolution" is the car accident which Jack, Ally and Callum are involved in. For this reason, it was important to get it right. I think I have written, and re-written, then edited, then re-edited, this part of the book in numbers that are well into double figures. It is a critical point. And luckily - or unluckily - for me, I was actually involved in a car accident a few years ago, so this put me well within my comfort zone. However, it did require me to think back to that time, and that was...interesting. I discovered, sitting on my couch late one night when everyone was in bed and the house was quiet, that I remembered more about what happened that day than I had previously thought.
When I started writing, the experience came out of my fingertips. I remembered how the car was suddenly upside down, that there was no noise and the air was literally buzzing around me, that everything happened simultaneously in both fast-forward and slow-motion. It was enlightening, to know that I could recall all this detail just by digging deep - by remembering and drawing on that on behalf of my characters. I hope it adds some realism to the story, when you get to read it.
By the way, this was our car after our accident. Four adults climbed out of this car with only minor bruises. It was truly a miracle. I'm so glad we got to say that, because Jack, Ally and Callum certainly didn't.