Doomsday is a pure combo mirror where whoever assembles their engine and protects it with Force of Will and Daze first typically wins, so proactive disruption and graveyard hate for their Thassa's Oracle line matter. Surgical Extraction can exile their Thassa's Oracle from hand/graveyard after seeing it via Thoughtseize, effectively fizzling their kill condition. The extra Cabal Therapy strips a protective Force of Will or their Doomsday pile plan before they combo off. Duress is replaced since discard-for-discard trades are close to symmetrical here and Surgical Extraction is a more targeted answer to their actual win condition; one Beseech the Mirror is trimmed to prioritize speed in this race.