What you see is Nate holding onto a rope, being dragged through the mud and shooting a vehicle, then climbing up the rope. This is core mechanics. You watch any interview with the devs and they will keep using this phrase, for good reason. The rope is a regular tool at your disposal during normal traversal in the game, as seen here from another demo:
Now imagine you are encounter a cliff face that can only be climbed by throwing your rope up it. You are climbing the rope, and suddenly some enemies pop their heads over the top of the cliff and start shooting at you. You press L2 to aim and R2 to start shooting at them, mid climb. This is exactly what is happening in the first gif. Presumably you are pushing forward to pull yourself up the rope towards the jeep. The reticule appears because you press L2 to aim, and you shoot the other vehicles and drivers. The reticule disappears because you release L2. You then continue clambering up the rope until you can pull yourself up the vehicle. Even though your character is being dragged through the mud, you are still in control of what you are doing.
It's core mechanics, and you can extrapolate like this for pretty much every moment of the entire 15 minute demo.