It's a fun and well crafted mission, with rewards for exploration and the freedom to beat the mission lots of different ways and I really enjoyed it. I hope you find the time to flesh it out more.

However after I beat it I was looking at the script out of curiosity and I realized I'd completely broken the biter progression on accident. When I beat the mission I was still on evolution phase two, with a evolution of 0.32. Somehow I'd avoided both of the triggers to get to three, and then you can't get to four or five if you're not on three. (the train left without me with no ore in it while I was exploring, and maybe it complicated things that the train spent 5-10 minutes colliding with a closed gate before I eventually went back over there to free it)