Letheia Labs: Secret

The Letheia Labs contains 3 hidden switches that open the locked room before the exit teleporter for extra loot.

First switch

The first switch is located inside the Observation Cell. To the far left of the slime pool, you will find a small switch that will open a conduit leading to a chest and another switch. This switch will open the first locked room.

Second switch

The second switch is hidden inside the Vents. To reach it, from the entrance of the Vents, head down, right, right, right, then up. Activating it will spawn 4 Tentabombs and 3 Moontants and open the second locked door.

Third Switch

The last switch is located inside the Aquarium. Right before exiting the Aquarium, dive at the bottom and you will find the switch near the bottom against the rocks.

With all the switches activated, you will have access to all the loot in the last room.