A couple of puzzles re: her pistol.
I'm thinking that this may not have originally been written as taking place in Florida, but rather somewhere like New York City. I suspect this, because of the way she bought the pistol, from a black-market dealer just like Travis Bickle in Taxi Driver, rather than at a gun dealer, which Florida is chock full of, even more so back in 1994 when this was released. It's not NYC!
Why would she have to go black-market in FL? In 1994, she could have just bought one legally at any gun dealer. The 1994 AWB hadn't kicked in yet when they filmed this, so magazine capacity wouldn't have even entered into it. Even if it had, the ten-round capacity limit wouldn't have stopped her from firing two rounds.
If she'd had any felonies (which would make legal gun purchase verboten) on her record, he'd have known about it, because he'd have run her name at work.
Florida was a very gun-friendly state, even back in 1994, having had shall-issue CCW since 1987! Barring a serious criminal record, not only could she have walked in and bought one, but also had a permit to carry it concealed.
In NYC the film would have fit perfectly, with the pond outside the city, perhaps just a little ways upstate. As it was, the critical point of the gun being "unregistered" fails, because you didn't have to register guns in FL, so the justifiable homicide would have been the way it would have gone. That would have killed the film at the halfway point, because there would have been no crime, but that's the way it is.