Turn around to the left just before bonking the ceiling, to retain upward momentum. Then morph while passing through the crab and go through the morph tunnel to the left.

Entrance condition:

{
  "comeInSpaceJumping": {
    "speedBooster": false,
    "minTiles": 3.5625
  }
}

Requires:

{
  "notable": "Cross Room Jump Morph"
}
"canCrossRoomJumpIntoWater"
"canPreciseSpaceJump"
"canMomentumConservingTurnaround"
"canMidAirMorph"
"canKago"
{
  "or": [
    {
      "enemyDamage": {
        "enemy": "Sciser",
        "type": "contact",
        "hits": 1
      }
    },
    "h_pauseAbuseMinimalReserveRefill"
  ]
}

Dev note: Jump low through the door with at least $1.4 extra run speed.