I agree with Ava on the point that following that shot is certainly not a good idea and it is dangerous, far more than going back.
Not something i would ever even consider under different circumstances.
A potential ally ? I mean, yeah we know she's a LI, the characters certainly do not.
Considering how they meet, i'd say taking risks for that possibility is not a good idea, neither out of empathy, sorry but the MC has his group to worry about, playing hero is a real bad idea and he should avoid taking risks when possible.
That being said, i do share your point that the MC needs to do something to for the survival of his group.
As they are they won't make it, their health is bad, they didn't get far and it's only getting worse. So far, that girl is the best (and only) source which could have either access or knowledge where they could get better gear.
Like much needed gas-masks, which would drastically increase their chance of survival, be it scavenging, better health or getting out of the city. Ideally some guns and ammo, but the chance to get gas-masks alone is something i would consider worth taking a risk for.
Hm, i think the reaction of her was rather understandable, especially if she had the pleasure of meeting other survivors who weren't as friendly. Certainly not a bitch, otherewise she wouldn't have helped them with the house and i doubt she has nefarious plans for them.
True, every time setting a foot out of the house can be deadly. Still, they should minimize danger when possible, not doing things like Laura and the MC did this ep, should kinda be common sense, or self preservation.
As for the noise, i think we can rule out the burned ones being attracted to it, if they don't react to a car moving by less then a meter away i don't think a gunshot would attract them. The witches, my guess is they can hear, but they strike me more as ambush predators which try to lure their prey to them...that is just a guess of course.
Still, it's a risk i would take.