Scene Context: After darkness falls, the temperature plummets, and the metal hull begins to creak and "fire off gunshots."
Essence of the Phenomenon: Due to its thin atmosphere, Mars bleeds heat very rapidly after sunset. Extreme temperature drops induce the thermal contraction of structures. In a metal hull, this manifests as sharp pops, bangs, and the groaning of the outer shell.
Scientific Basis: NASA explicitly notes that Martian nighttime temperatures can plummet to roughly -90 °C or lower, while daytime surface temperatures can be significantly warmer. Under such drastic swings, thermal control becomes a matter of survival, and the sharp contraction of materials is a direct consequence of standard thermodynamics.
Current Limitations: The hull "gunshots" in the scene are not exotic Martian fiction. They are the expected mechanical acoustic emissions of a cold metal shell undergoing a rapid thermal drop in an environment where thermal control failures quickly become lethal.