Against the Russians, that is (and judging on the behavior of the Russian soldiers, can't say I would have blamed them). Had it been the Americans or British, it would have been an entirely different story. They would have surrendered in droves.
Look, the entry of Americans into WWI didn't send the Germans flying to POW compounds, and our entry in WWII didn't either. They would have fought. The difference in WWII was the Russians didn't abandon the field of battle the way they'd done in WWI with a separate peace with Germany.