I was re-watching BvS recently and it appears to me that after Wonder Woman cuts off Doomsday's hand, he blasts her with heat vision causing her to lose her sword.
Somehow the sword gets entrenched in Doomsdays' stump of an arm and he manages to integrate it (grow around it) to his body. And it is the sword that he uses to stab through Superman's chest.
At this point Wonder Woman no longer has her sword and pulls out her most powerful weapon... the lasso.
Anyone else notice this?