Time the Crystal Flash so that the Oum can hit Samus. This is fairly lenient, but one method is to Crystal Flash near the shot block pillar while the Oum is to the right of Samus, near the door.

Requires:

{
  "obstaclesCleared": [
    "R-Mode"
  ]
}
"canRModeCrystalFlashInterrupt"
{
  "ammo": {
    "type": "Missile",
    "count": 10
  }
}
{
  "or": [
    {
      "tech": "canComplexRModeCrystalFlashInterrupt"
    },
    {
      "ammo": {
        "type": "Super",
        "count": 10
      }
    }
  ]
}
{
  "or": [
    "h_fullEnemyDamageReduction",
    {
      "and": [
        "h_partialEnemyDamageReduction",
        {
          "resourceAtMost": [
            {
              "type": "RegularEnergy",
              "count": 49
            }
          ]
        }
      ]
    },
    {
      "and": [
        {
          "resourceCapacity": [
            {
              "type": "RegularEnergy",
              "count": 199
            }
          ]
        },
        {
          "resourceCapacity": [
            {
              "type": "ReserveEnergy",
              "count": 199
            }
          ]
        }
      ]
    }
  ]
}

Resets obstacles: R-Mode