A new video just came online that seems to show several Rogue One characters suffering a fate different than the one they have in the film.
These are pretty big spoilers so, just in case...
OK, so Making Star Wars noticed that the below ABC News video about the making of K-2SO features on-set footage of K2 being gunned down outside a bunker on Scarif. It also looks like Cassian is lying down besides him. Check it out. The shots in question are at from 0:44-0:51.
And here's a GIF of it.
We're pretty certain that, at some point, both of these characters died in the film in a different way than we see in the film. That's because of footage released of them running on a beach with the Death Star plans. However, it's also possible this particular footage isn't of them dying, just being hurt. In fact, if this footage does in fact link to that beach shot, that makes the most sense. How could they die at the bunker, but then be running across the beach, away from the bunker?
Then again, Alan Tudyk's fall seems pretty "dead" to us and we also know Gareth Edwards shot stuff that was not for the movie.
Basically, we don't know exactly what this is, except another piece of evidence for the rogue Rogue One cut that we'll never see.