Enter with G-mode direct, back up to between 1 and 6 pixels from the door transition, and activate X-ray to get very deep stuck in the door. Climb up 1 screen, and perform a turnaround buffered spin-jump away from the door to trigger the transition, bypassing any lock on the door. If Phantoon is not defeated then you have to move quickly to prevent the Coverns from hitting you.

Entrance condition:

{
  "comeInWithGMode": {
    "mode": "direct",
    "morphed": false
  }
}

Requires:

"canXRayClimb"

Bypasses door shell: true