Sons of Russian Immigrants and Russian Roulette
Is it a coincidence that Mike, Nick, and Steve have Russian ancestry and they later play Russian Roulette? This may sound out of left field, but recall that in the first hour of the movie, you see and hear lots of Russian songs and dancing, and even hear one of the grandmothers speak Russian to the priest. Then, a Russian Roulette "game" in the POW camp.
The scene that triggered this thought (no pun intended) was when Nick was asked if his last name was Russian, and he replied "No, it's American." An hour later, this man is addicted to Russian Roulette. Seems like these two themes are connected.