What that movie reference in 'The Last of Us' episode 6 means for Joel and Ellie

Trekking through an America overrun by zombie-making fungus, not to mention raiders and tyrants vying for power, Ellie (Bella Ramsey) and Joel (Pedro Pascal) finally found some respite in episode 6 of The Last of Us. They even have the chance to watch a movie, 20 years after the world as we know it fell to ruin. But what is the...