Complex sentence: His henchmen throw Ivan to the river but he manages to hold on to the railing at the last moment and crawls up on his stomach all the way back up and manages to activate the current that destroys the container.
Split into simpler sentences: His henchmen throw Ivan to the river but he manages to hold on to the railing at the last moment and crawls up on his stomach all the way back up. He manages to activate the current that destroys the container.