Works in all game modes. It reads 3 z-coordinates of camera (not actual player position) periodically
and calcs speed and acceleration. If speed falls into danger zone ( fatalv 1.25 fatalv ) checking for decceleration is enabled ; once decceleration occurs, player is killed.
So any wild movement puts you in wounded state; there mild deccelarations kill. For even more realism secondary health could be added. Once it is depleted, player is killed.
To prevent unnecessarr bugs use firstperson view and set thirdpersondistance 0. Note that fall speed ( as coded in source of game ) is not a function of fall height but but of the time spent falling.