Wait for the acid to go down before entering the Morph tunnel, and again once reaching the other side.

Requires:

{"obstaclesNotCleared": ["B"]},
"Morph",
"canSuitlessLavaDive",
"canCarefulJump",
{"heatFrames": 700},
{"acidFrames": 15},
{"or": [
  "canDash",
  {"heatFrames": 50}
]}