I just watched the movie AGAIN..............and i noticed something funny.........its in the beginning when Enns near the trailer and Aguire drives in like he is going to drive right into the trailer.....Ennis quickly moves out of the way....just one quick movement, but i thought it was funny.....and i could picture Ennis thinking...."holy shit"
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Yes, I like this detail, too

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Another subtle detail follows shortly after: when Aguirre gets up the stairs and opens the door of the trailer, Ennis begins to step up the steps too, to follow Aguirre inside. But Aguirre just slams the door behind hisself, more or less directly in Ennis' face, without any notion to Ennis (or Jack) to follow him. So Ennis steps down again, unsure of what to do. He even shoots a brief glance in Jack's direction.
Why does Ennis glance towards Jack? Because he feels embarrassed and wants to know if the other guy has noticed? Or to see what Jack's doing, if he shows any intent to follow Aguirre without invitation on Aguirre's side?
Hm. I think it's the first, he's self-conscious because he has wrongly assumed Aguirre follows the usual rules of politeness.