Requires:

{
  "not": "f_DefeatedPhantoon"
}
"canRiskPermanentLossOfAccess"

Exit condition:

{
  "leaveWithDamage": {
    "enemy": "Phantoon"
  }
}

Dev note: Not likely to be possible, as it requires canRiskPermanentLossOfAccess and Phantoon alive with the door unlocked.