Rejuvenation Chamber gives you incremental life gain to keep pace with the life they gain from Exalted Angel and Gerrard's Verdict, buying time against their grindy removal-heavy plan. Defense Grid makes any spell cast outside its caster's own turn cost {3} more. Against this deck that taxes their instant-speed Swords to Plowshares (and Funeral Charm or Skeletal Scrying) when cast on your turn, pushing their interaction onto their own turn. It does not tax their sorcery-speed Vindicate or Gerrard's Verdict, or anything else they cast on their own turn, and it taxes your own spells on their turn as well, so it is a modest slowdown rather than a lock. Winter Orb is risky since it restricts you as much as it restricts them. Phyrexian Furnace stays in because it can exile Eternal Dragon from their graveyard and blank Skeletal Scrying. Shield Sphere comes out because their creature base is mostly fliers, which a 0/6 defender cannot block, so it does little in this matchup.