You seem to be the queen of opening lines LS! Even though the point of view and tone is different than the sequels, it flows well into them while keeping your own voice.
The tension really builds here. It’s great. One suggestion: Maybe specify the type of gun in the second paragraph? (i.e. “contours of the oiled Colt” or whatever) I think it would make the actual word “gun” stand out more if it were more sparsely used.
You know, the only reason I didn’t was because I know diddly about guns? I thought about asking Geebs what he had in mind, aaand… I didn’t. Because specifying a make had ocurred to me! I think I’ll do some research and change it.