CONTROL Resonant Underpass Resonant: Three Astral Keys

Enter the Astral space

Follow the story into Underpass through Recursions and Iterations. At The Spire, inspect the elevated eye to reveal the area. From the Fast Travel point, climb the red blocks on the left and use Gravity Shift to continue upward. Clear the enemies holding the red barrier, then enter the white light. Cross the floating approach to the locked-door hub. PowerPyx route

Three key routes from the locked door

Complete the branches in any order. Return to the hub after each key; do not count doors opened as keys collected.

Branch	What to follow	Key landmark
Left	Use the crate levers, wait for spikes to retract and cross the left gap without immediately shifting. Turn right after the next lever and climb the brown furniture pillar.	Cube beside a wooden table and chairs
Right	Climb the island's pillar, follow the gaps and furniture surfaces, catch the shifting pillar and cross the stair-side platforms.	Cube at a bed
Behind / across the hub	At the unreachable upper floor, climb the nearby right-hand pillar and cross with Gravity Shift.	Cube on a desk

These are route landmarks, not coordinates. Confirm each pickup with the Astral Key notification. Furniture becomes a traversal surface when gravity changes; a route that appears to end below a floor can continue over a pillar. Method's detailed branches, landmark cross-check

Open the doors and finish The Physicist

Spend the keys on the consecutive doors, then hold the mirror interaction to enter the encounter. Move through projectiles, jump the sweeping arm and retreat from ground pulses. Destroy the split orbs to reform the boss; follow between arenas and use the finishing prompt. Method boss route

Choose one ability

The reward is Spike or Astral Rebuke, rather than both together. Spike provides a continuing summon attack; Astral Rebuke provides a homing ground eruption. Choose for the role missing from your loadout, then check the completed Quest Log entry and the Untapped Golden Earrings reward. The Untapped item still needs Artifact Formation before use. PowerPyx completion

Continue with the Artifact crafting guide or return to the story walkthrough.