Back into the doorway on the left side of the room, and precisely jump under the floating platform. This requires a frame-perfect jump and frame-perfect release of jump. Samus must also aim down any time before reaching the left side of the floating platform; this can work as early as the first frame after jumping.

Requires:

{
  "doorUnlockedAtNode": 3
}
"canInsaneMidAirMorph"

Exit condition:

{
  "leaveWithMockball": {
    "remoteRunway": {
      "length": 5,
      "openEnd": 1,
      "steepDownTiles": 1
    },
    "landingRunway": {
      "length": 4,
      "openEnd": 1,
      "steepUpTiles": 1
    }
  }
}

Unlocks doors:

{"types":["ammo"],"requires":[]}