The performers in the river scene were Hannah Betts as Cara Gee’s double, Callie Croughwell and Alice Ford as Buck doubles, and me as Buck breaking through the ice surface with Cara hanging onto my back.
When it came to Buck’s involvement, we had a Buck double that actually performed the scene as you saw Buck do in the film.
The execution of this scene was comprised of almost entirely real elements, from the river built from shipping containers to the ice covering and breaking hole in the ice, as well as the underwater rescue all required little CGI.