What is an “instant” death anyway? How long is an instant? Is it one second? Ten? The pain of those seconds must have been awful as her heart burst and her lungs collapsed and there was no air and no blood to her brain and only raw panic. What the hell is instant? Nothing is instant. Instant rice takes five minutes, instant pudding an hour. I doubt that an instant of blinding pain feels particularly instantaneous.
No point in thinking, you just have to get on with life. We only have one after all, we should try and do our best. We can never get it right, but we must try.