"but will soon head down into the thick bottom"
No shot because of the horizon--I don't know my back stop. Since I think he's headed down, I'm waiting for him to take a few steps so my exiting bullet hits the dirt.
For those that took the shot, I don't think that is a bad choice. I agree that the bullet energy after traveling across the canyon and plowing through the elk is minimal, so it doesn't go far. Still an unknown, though, and I like control.