the HK-Aerial Terminator
With the noise that thing made in the film, my first thought was that it couldn't possibly hear anything. It likely tracked its victimes via radar or infrared. The fandom wiki says nothing on how it tracks, it just gives gushing praise on armaments and troop-carrying capacity.
From what I recall from the movie, soldiers on the ground were pretty much able to move around freely as long as they stayed out of line-of-sight. They could even talk, but of course, military talk, not table-side chit-chat.
Of course, having read about how we already have companies with "vast experience in filtering unwanted noise", there could well be a new timeline where the buggers can filter out their own engine noise and hear a human running. From there, we're one step away from an area-of-effect missile showering an area 50sq meters around the supposed location of the sound, and that goose is pretty much cooked.