The New Zealand Division attacked toward Passchendaele across flooded ground and lost more than two thousand men in a single day, over eight hundred of them killed: the country's heaviest loss of life in one day, in October of 1917. The stretcher-bearers worked through that night and into the next, and the chaplains with them, in rain, over ground that would not hold a man's weight. A great many of the dead were never recovered; their names are on the memorial wall at Tyne Cot, and they are still read aloud each year.
The barrage lifted on a timetable set for firm ground, and the men couldn't keep pace with it through water-filled shell holes, so it was ahead of them within minutes and the uncut wire was still standing. Carrying out a single wounded man took six or eight bearers and most of a day over that ground, often more than two miles to the nearest aid post.
Carrying a stretcher a single kilometre over that ground took six or eight men and often several hours, and it still had to be done again and again through the night. Many of the wounded reached a casualty clearing station more than a day after they fell. The bearers knew it and went back out anyway.