Requires:

"Gravity"
{
  "or": [
    {
      "getBlueSpeed": {
        "usedTiles": 22,
        "gentleDownTiles": 4,
        "openEnd": 0
      }
    },
    {
      "and": [
        {
          "getBlueSpeed": {
            "usedTiles": 23,
            "gentleDownTiles": 4,
            "openEnd": 0
          }
        },
        {
          "doorUnlockedAtNode": 4
        }
      ]
    }
  ]
}

Clears obstacles: A

Unlocks doors:

{"nodeId":4,"types":["ammo"],"requires":[]}