In the last segment, you'll see a fireteam is charging towards the fallen. If you look up at the twilight sky (on the moon?) filled with the stars of the Milky Way, you'll see what looks like a satellite pass overhead.
Here's a link to a screenshot to give context to the gif, http://i.imgur.com/ErYG61K.jpg.
btw, could we get a high quality desktop background from the TYDC video at 2:09, much like this image? Imagining three Gunslingers taking on the moon together under that sky brings a big smile.
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Looks like a satellite, but it's either a damn big one or it's flying lower to the surface than one might expect (and than would be physically practical without SPACE MAGIC! Drag would have that sucker on the surface in a heartbeat, and it's not wrapped in fire). Satellites in orbit are pinpricks of light, all reflective surfaces and shininess, not dark objects passing close overhead. It's intriguing, whatever it is.