Overall I liked your script, a few things i might change if you're interested:
The innocent Maid girl seems a little stereotyped, and her transformation/falling in love a little obvious. I think all it would take would be a few details to make it interesting, maybe some violence in her past, scars, whatever. Also some more moments between her and George, or something a little unique in their relationship, instead of just eyeballing eachother and jumping in bed.
I like the corrupt law enforcement, but it could be set up a little better. its one thing for an agent to steal some random money, but killing for it? a marshall would know the chances of walking away from that, and would have to have a real reason to think she could get away with it. this could also be set up earlier with the other deputies and such that you have. if you just took a moment to show them, and made them a little morally questionable, it would kind of make the whole world of crooked cops more believable.
I'm all for bad guys getting away in the end, I think that's excellent, but there has to be some kind of price for what they've done, especially since you say that this was their first jump to murder from armed robbery. Even if they buy their way out of the marshalls eye they still pay psychologically or with their relationship with each other. I don't think this needs to be spelled out, just maybe imply it with the last couple of shots, so it's not a driving away happily ever after kind of feeling.
The best thing about the ending is the sudden tight shifts right at the end, when the person in control shifts quickly from one character to the other. I would definately play this up, and make sure the characters are properly set up. You might isolate that final scene from the rest of the violence so it doesn't just get lost in the random shootout, even if just by a moments rest.
Seemed pretty similar to the movie Way of The Gun, which would normally be a compliment, but its maybe a little too similar.