The three Gerutas can be farmed while trapped. Run the rest of the way to the left door and use heat damage to interrupt.

Entrance condition:

"comeInWithRMode": {}

Requires:

"f_ClearedSpeedBoosterLavaTrap",
{"or": [
  "h_CrystalFlashForReserveEnergy",
  {"and": [
    "h_heatProof",
    "h_RModeCanRefillReserves",
    {"resourceMissingAtMost": [{"type": "Missile", "count": 0}]},
    {"partialRefill": {"type": "ReserveEnergy", "limit": 20}}
  ]}
]},
{"or": [
  {"and": [
    "h_speedButSlow",
    {"simpleHeatFrames": 560},
    {"heatFrames": 60}
  ]},
  {"and": [
    "h_speedDash",
    {"simpleHeatFrames": 310},
    {"heatFrames": 40}
  ]}
]},
"h_shinechargeMaxRunway",
"h_heatTriggerRModeSparkInterrupt"

Clears obstacles: A