The sand does not impede Samus in G-Mode. Enter the room on the right half of the transition, where both Evirs will be off camera to avoid their projectiles.

Entrance condition:

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

Requires:

"h_navigateUnderwater"
{
  "or": [
    "canInsaneJump",
    {
      "enemyDamage": {
        "enemy": "Evir",
        "type": "particle",
        "hits": 1
      }
    }
  ]
}
{
  "or": [
    "Gravity",
    "HiJump",
    "canSpringBallJumpMidAir"
  ]
}

Dev note: Only the last jump needs any items.