"The astonishing fatality rates that can be found in so many battles in the First World War weren’t accidents or unfortunate byproducts of the technology – they were factored into the battle plans.
By the nature of attritional warfare it was calculated how many men would be lost every week and commanders drew up enough reinforcements to replace them. This was called “Normal Wastage”."
That 100% death rate is not true actually.
At least one person survived.
Search for "Jeanna Giese" for more info.