"Treat your enemies like you'd want to be treated yourself"
The russian concept is shooting surrendering soldiers, executing them in front of a camera or torturing them to death.
The russians are expecting to be treated the same way either by the Ukrainians or by their own side when they get exchanged.
Also, and this is in line with what shonima said russians simply don't value life the same way. Suffering, depression and depravity is part of the national identity. "Such is life" should be made the national motto.