WARNING, SPOILERS AHEAD: Since “No Country for Old Men” was released two-and-a-half weeks ago, there’s been much debate about what actually transpires during the last 20 minutes of the movie. But it seems the mystery’s been solved. At a lunch held for the Coen brothers on Tuesday at the Four Seasons, Javier Bardem was happy to explain Josh Brolin’s cause of death in the film. “The Mexicans kill him,” Bardem said, laughing. “But I get the money.” Ethan Coen said he wasn’t surprised people were having trouble figuring it out. “We knew that it was an unconventional way to end a movie. What’s been surprising to us is that it’s played much wider than we thought it would.” The film grossed nearly $8 million last weekend and is expected to receive a few Oscar nods.