I always found the accounts interesting, that they would have these wounded guys who lost a lot of blood so pumped up with plasma that their faces looked like people who had been painted waxy-white because they has lost so many blood cells...it was a characteristic look you saw everywhere there were wounded men.
Maintaining hydraulic pressure. We are machines. The machine's components can only perform with a tightly regulated range of hydraulic pressures. That and a barely maintained level of red blood cells carrying oxygen.
That is why you don't poke a dead person's face. It makes it very difficult to pop the dent back out for the funeral.