As Klaus mentioned, I'd try a few things before taking it to the dealer if you have the time. My dealer would steal from his own mother so I avoid him like the plague unless necessary. You have a no crank situation that points to your starter system vs the ignition but I'd at least look in your "ECU Box" to see if there is water inside which I'd doubt. It's a black box on the passenger side fender in front of the radiator expansion tank. Has a black plastic tube that runs from the radiator shroud to it. Cover snaps off. Look inside with a flashlight for water.

As it ran after the incident, this probably isn't the case but water in a cylinder will prevent the engine from cranking. The engine is said to be hydrostatically locked. Even if this is the case, you should still hear the starter selenoid click but maybe not. You said you had the plugs out. Did you notice if any were wet? The quick way to check this is to remove all plugs again all at once and then try cranking the engine. If HL is present, the water will be ejected from the plug hole(s). I doubt this is the problem but on an engine partly submerged, it'd be on my suspect list. Easy and free to check and worth a try before taking it in.

bl