Back in the early '90s I did a combat lifesaver class with my platoon. Lots of good trauma care instruction by a 20+ year, crusty old E-7 Army medic.
At the end we had to qualify on a simulated casualty. He had some hapless E-2 playing victim. Had him all decked out in simulated wounds complete with dyed karo syrup hooked to pumps. (Ruined a set of BDUs, I was barely able to save the boots I wore that day.) The victim thrashed around and moaned and screamed while you were trying to treat him. He really played his part well.
You had to evaluate and treat the wounds in order of severity all while he and another senior medic hovered over you, screaming at you that you were doing the wrong thing and you were going to kill the patient.
It was kind of intense.
I think that was more useful than working on a dead body would have been.