The door is locked and the cold water is still coming in. You could still break the door down, though, if you can endure the cold.

Endurance: Break down the door.

Otherwise, you may examine the mural.

Or hope that the water is just an illusion.

Strict Mode (In Strict Mode, the game will not show you options that require a skill you do not have. In non-strict mode, these options will be greyed out but you can still cheat and access them. You can switch modes at any time.)