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",
  {"and": [
    "h_underwaterCrouchJumpDownGrab",
    "h_storedSpark",
    {"shinespark": {"frames": 7, "excessFrames": 6}}
  ]}
]}

Dev note: Only the last jump needs any items.