Complex sentence: A videotape informs him that crushing his hands in a pair of presses will release him; he does so, but the blade still swings down and violently cuts him in half, while someone watches through a hole in the wall.
Split into simpler sentences: A videotape informs him that crushing his hands between the presses will release him. He does so, but the blade still swings down and cuts him in half, as someone watches through a hole in the wall.