I hate to sound like a broken record but again this is up to you. Many beginner writers find writing in the omniscient third person the easiest...
Maybe instead of a knife your character could use an item from the car or the accident itself. A piece of glass from a window? He can just...
The Hours, Michael Cunningham Mrs. Dalloway, Virginia Woolf The Time Traveler's Wife, (?? forgot!) But maybe you'll want to develop your own...
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