An easy way is once Samus is on the top platform, jump and aim down to lower the camera, then place 3 PBs.

Requires:

{
  "enemyKill": {
    "enemies": [
      [
        "Metroid",
        "Metroid"
      ]
    ],
    "explicitWeapons": [
      "PowerBomb"
    ]
  }
}
{
  "or": [
    "canMetroidAvoid",
    "canCameraManip"
  ]
}

Clears obstacles: f_KilledMetroidRoom2

Sets flags: f_KilledMetroidRoom2