I never tried dropping my film in a lake, before or after exposure.
But i do keep it in the freezer.
The rather simple solution to the condensation problem that presents itself when you take something out of the freezer is to keep the packing closed until the thing has warmed up.
That way, the condensation still forms. But the thing that the condensation is dripping off is the outside of the packing. What's inside will remain as dry as it was when it went into the freezer.