My priority at that moment was to take out anyone near the ball carrier.
At 3:03, I notice reinforcements are arriving. I kind of relied on my team to slow them down.
At 3:13, this is my favorite spot to set up shop if I predict the enemy ball carrier would go this route. I want the ball carrier to try to bypass me. Why? So I can use cover pulse to knock back the ball carrier down the next level. And this is where I am supposed to time my stun immunity (entrench), so that I don't get knocked back myself. I would time my AOE (Orbital Strike), so that the enemy ball carrier would walk right into the damage of the AOE (as seen in 3:19). Also, I can take advantage of my group shield, which grants 20% damage reduction to anyone near me. By staying at the original spot at 3:00, I couldn't have used my knock back or my group shield.
However, in future Huttball matches, maybe I will try staying where you originally wanted me to stay to see how that goes. Maybe it's better if I shoot them from a safe distance instead of "being in the action" at 3:20.