In spades, from Starinski's barbed-wire constriction to Quinn's barbed-wire... uh... invasion to Chevasse's impromptu leg surgery, taken care of by the local trench rats, among much else.
Many of the character's deaths are horrifying, but McNess' might just take the cake. After being tormented by hallucinations and fleeing into No Man's Land, he is shot by Bradford and left barely able to move. Just as he sees Doc approach, thinking that he's saved, he is suddenly attacked by an unseen creature in the mud that slowly drags him into the ground, with Doc desperately trying to drag him out as he screams until the mud overcomes him. Terrifying.