I think Lorraine understood that the creature can do things humans can't. It attacked that first miner from above. It used a jump attack on another miner. She was rightly cautious in suggesting the Alien could get out and follow them back to the colony. I thought Hanks was having a Gorman moment watching the miners die. 'Droid or not, she may have been having some sort of inner conflict about her orders.
I liked the ending, but it was wrong. There was nothing clever, furtive, or sneaky about the Alien's approach. It charged into 3 armed and waiting humans with animal rage. Intellectually, it had more in common with the Covenant xeno than the original Big Chap. Outcome: Death for all. I expect the miners would inflict grievous harm with their mining drills, but the Alien would bathe any survivors in its acid blood. Game Over for all of them.
Also, it looks like life in a W-Y colony sucks! These miners are killing themselves just to get by, and the job is generational. There's no upward mobility, no stability, and no guarantee The Company will not sacrifice them to get hold of a lethal alien lifeform. Definitely a dystopian future.