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The best thing to do for such a case is, to remove the battery at once and not try to power it On.
The chances are, frankly and honestly, still not good. Brine, since it contains salt, will corrode the interior. The one hope is, if no power was applied to the circuits at the time, and not much residue of salts is left behind, then maybe the camera will not prove damaged, once it is thoroughly dried out.
Thorough drying out will be needed, with a salt-water case like this. The least bit of salty dampness, when you next power On the camera, will prove quite deadly to circuitry.
Open all hatches. Remove the battery (though I said that already) and leave the battery hatch propped open.
Place the camera in a dry, warm or hot, dust-free undisturbed location. Keep it there for at least 4 days continuously, perhaps with some silica gel dryer packs near it, or even dry white rice (after blowing the chaff and dust out of it, and if you're careful not to get it actually near, touching, nor into the camera, it can be quite useful for drying purposes if you don't have silica gel.)
Only after 4 days, should you insert the battery again, or try it out. It is vital not to power it On, until you are certain it is dry.
Let me know how it goes, once that process is completed. It does not have a good chance of success, but there is some hope still for the camera's operational condition.