Get to the left side of the room while avoiding the hole in the ground, jump up through the Morph tunnel. Jump up to the ledge with either Gravity, HiJump and a Crouch Jump Down Grab, or a maximum height Spring Ball Jump.

Entrance condition:

{
  "comeInWithGMode": {
    "mode": "any",
    "morphed": false
  },
  "comesThroughToilet": "any"
}

Requires:

"Morph"
"h_canNavigateUnderwater"
{
  "or": [
    "Gravity",
    {
      "and": [
        "HiJump",
        "h_canCrouchJumpDownGrab"
      ]
    },
    "h_canMaxHeightSpringBallJump"
  ]
}