He is also an easier kill when he is reloading, and I seriously doubt the AI alien would care if you are reloading or not. Probably scripted, the AI humanz gotta go first. But at least they could haveve placed the AI human closer to the alien, this way is just weird. "Wait in line, you will be attacked next, please."
It looked good to me when the pred was attacked by more aliens, 1 alien acted differently than the others which made me think that the AI was improved.