You shouldn't have been driving out there so I don't feel bad for you.
That said, I doubt that you hydrolocked it. If the water wasn't high enough to get into the interior, it likely wasn't high enough to be sucked into the filter. This car as three air inlets. If one is submerged, it will pull air from the hood or grill openings. The water would have to be up to the hood, to the point where it could physically flow through the filter, to hydrolock it.
You most likely fried a module or something.
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R