Dimir Excruciator leans on Deceit, Bitter Triumph, and Theorix Charm to disrupt and remove your threats, so Duress strips Bitter Triumph, Theorix Charm, or another key noncreature spell before it resolves (Deceit is a creature, so Duress can't take it). Erode is weak here since their deck is light on cheap creatures and lands they'd fetch would just smooth their mana. Seam Rip stays on the bench, since nearly everything they play costs more than 2 and it would have almost no targets. Keep your core lifegain engine fully intact since Amalia, Haliya, and the Case are what actually win the race against their card advantage plan.