I agree with everyone
a) dont' dig near humans. They are a highly paranoid species ...
b) examine if plants are re-plantable; they might be more happy inside. (also, if everything is inside, we are _much_ harder to find
c) try to determine the nature of Them
d) perhaps examine the flying thing to determine more of the nature of their sensors, commuication and method of flying?
e) focus digging on ice, and the deeper tunnles. Defining Our current Height to be 1 Splaz, Is there any reason why we shouldn't treat -100 Sp. as the default depth for Our tunnels; atleast it should be nice and warm at the default depth.
Unless otherwise specified all tunnels should have a 5" downward slope.
As an extra note, when seeking minerals, deeper is better, as the near surface has probably been searched by the humans for simple deposits. (RE: reference to deposit 30 "kliks" away)
We should build a recycler. Then the only elements to escape will be via any gaseous outlets.
Finally, no magma available; no magma flows of any types have ever been observed on Mars; the newest outlet is possibly 20 million years old; the newest in the area where we are are around 100 million, and many areas are over 800 million years old.
The average elevation is 2-3km, so we may have to dig more than 4km down to find anything more than warm rock.
Geothermal is possible, given we have a functional heating tube, but a 200' difference isn't going to generate that much power, although we could design a flower to take advantage of thermal differences ...