What does evacuated mean in "evacuated by their captors, and mountains of dead bodies."?
The liberators were met by some seven thousand skeletal prisoners who were too weak to be evacuated by their captors, and mountains of dead bodies.

I understand that captors can evacuate people, but how can dead bodies evacuate people?

Question

What does evacuated mean in "evacuated by their captors, and mountains of dead bodies."?
The liberators were met by some seven thousand skeletal prisoners who were too weak to be evacuated by their captors, and mountains of dead bodies.

I understand that captors can evacuate people, but how can dead bodies evacuate people?

Answer

The liberators were met by:
a) some seven thousand skeletal prisoners, who were too weak to be evacuated by their captors, and 
b) mountains of dead bodies.