Before the Fall (2004)

The underwater shots of the lake scene toward the end of the film were done in a test basin with warm water and artificial ice.

Christoph Schneider. Pull yourself together!
Albrecht Stein. Pull myself together? Do you know what we just did? You shouldn't have shot! You shouldn't have shot!
Tjaden. I didn't give the order. Your father said they had guns!
Albrecht Stein. Why are you looking at me like that?
Friedrich Weimer. I'm not looking at you.
Albrecht Stein. I.

During Friedrich's glider flight, his helmet is securely strapped at the start but is shown unstrapped a few seconds later. He kept both hands on the glider's yoke.