I don’t think that’s a particularly accurate description of the book. Sure, the stories are told in the past tense, but that doesn’t mean that there isn’t plenty of action. The guy collecting stories is basically a bookend on each chapter and some occasional interjections. It’s an effective storytelling technique, but the meat of the book is in the stories themselves. And the vast majority of the stories are stories of individual high-energy action sequences. You’ve got the doctor dealing with an early outbreak, the pilot cut off from support and fleeing through the woods, the combat vet in the midst of a battle gone wrong, etc. Only a few of the stories (the one about the SAfrican guy comes to mind) are really about the aftermath.
Saying that “really there’s no action in it at all” is like saying that The Princess Bride doesn’t really have any action in it; it’s just a movie about a guy reading a book to his grandson.