I, too, was confused when I first started by the pronunciation in the film. The sad truth is that the actors didn't always pronounce every word correctly, and if it was a good take, they didn't always stop to redo it.
Px, kx, tx are called ejective consonants because, true to their name, they should "pop" out of your mouth, and then there's kind of half a pause after them. Don't worry if you don't get it perfect at first, just try your best.
There is a whole thread dedicated to them here
, and many auditory examples of how they should sound are available around the forum, as well as there.