have same question. Where is the switch for the sewer help

[truckermanswife]

Wanderintowns and I both have the same question. Can you please tell us where the switch is to get out of the sewers. I am fed up with random battles. Is it in the area where the party commented on someone studying down here or where the blue frog is. I saw the square pools but no switch. Just a locked gate with door behind it to the left. Thanks any help is appreciated.

Truckermanswife