This is so funny. With the exception of that idiotic computer generated image (which means nothing), the images you post show that as one runs the hips sway enough to bring one buttock in front of the other changing the angle from which a projectile could enter, not to mention the common sense of it.
You are one weird dude.
It is funny to you since your unconscious reaction to the evidence is the source of the humor. First the "idiotic" computer generated image uses precise measurements to model human anatomy in the process of running. It is a simulation of that process, thus it is a prime example and evidence of the process of running. You many ignore the simulation, but I think most anybody with an open mind and the capability to reason will see that hips do not "sway" back and forth in the process of normal running.
Second, the images clearly show that legs extend, but hips remain aligned with the shoulders of the runners except in the case of the runner who is looking back over his left shoulder.
Third, buttocks don't move one in front of the other except in relation to another point. If the point is directly behind the runner, all that happens is that one buttock is closer to the point than the other buttock. The entry path essentially remains the same, parallel to the runners path. If, however, the point is offset to either side of the runner, the entry path will be at an angle to the runners path. Since, Davila was running directly away from the agents, the path should have been parallel to his path. It was not. He was turned.