Freeze one of the Menus (bugs) in a position where you can use it to get into the morph passage. One of the easier methods is with a damage boost. Stand in the water, take a hit for positioning, and freeze the bug near but left of Samus. Then morph on top and damage boost into the morph tunnel as it unfreezes.

Requires:

{"notable": "Frozen Menu Bridge"},
{"noBlueSuit": {}},
"Morph",
"h_navigateUnderwater",
"canTrickyUseFrozenEnemies",
"canNeutralDamageBoost",
{"obstaclesNotCleared": ["A"]},
{"enemyDamage": {"enemy": "Menu", "type": "contact", "hits": 2}}

Dev note: FIXME: There is a damageless variant where Samus jumps high before morphing, giving a small bounce as she lands on the bug to get through the tunnel. FIXME: This could be done with a blue suit, with greater difficulty.