Knock the crab off the wall immediately and then quickly freeze it. Preparing and auto canceled Super before entering the room could make this easier.

Entrance condition:

{
  "comeInNormally": {},
  "comesThroughToilet": "any"
}

Requires:

"h_navigateUnderwater"
"canTrickyUseFrozenEnemies"
{
  "or": [
    {
      "resetRoom": {
        "nodes": [
          3
        ]
      }
    },
    "canPrepareForNextRoom"
  ]
}
{
  "or": [
    "canInsaneJump",
    "Spazer",
    "Wave",
    "Plasma",
    {
      "and": [
        "canDodgeWhileShooting",
        {
          "ammo": {
            "type": "Super",
            "count": 1
          }
        }
      ]
    },
    {
      "and": [
        "canDodgeWhileShooting",
        "HiJump"
      ]
    }
  ]
}
{
  "ammo": {
    "type": "Super",
    "count": 1
  }
}

Resets obstacles: A, B

Dev note: Kinda tough with no other beam/missile/super/movement.