Unfortunately, this does happen as is seen in a recent report:
http://bangordailynews.com/2013/09/...itness-to-testify-against-her-alleged-abuser/
Working as a therapist with traumatized individuals, I can only say how deeply incidents like this sadden me. I truly wish those who felt they were doing the right thing by further legally ravaging a victim who has been brutalized and then abandoning them could live in the shoes of those people for a month. Yes, they need to be helped to testify but not by arresting them. People are under the mistaken notion that they are being picked up and put in some sort of protective custody, that's not the case.
When arrested, the police come to where you are and place you in handcuffs. For a battered partner it can lead to panic responses that get interpreted as resisting arrest. That traumatizes those around you, including kids, and creates all sorts of mistaken beliefs. Arrests are public record, putting your information on display and creates a criminal record for you. Yes, even though you committed no crime, you now have police profile. You are booked, photographed, fingerprinted and have to find someone to post your bail just because you reported being raped or assaulted. The message sent to women in domestic violent homes is (1) endure silently because you know what to expect or (2) seek help, be arrested and potentially lose your kids. [Yes, there is more I could write on this but it is a reality.]
It's like courtmartialing a POW suffering PTSD from torture because he managed to escape and doesn't want to go back into battle. In counseling vets, we make them safe, give them a place to process what they've been through, then assess if they're ready to go back into battle. These DV survivors have PTSD as well. If a deposition can be taken, the material witness warrant is unneeded. A trained police investigator should be sent to the home to take a deposition. The DA should appoint a Court Victim Advocate to assist her upon the perpetrator's arrest. The failure to protect and support the victim by abuse of power is unethical and immoral though perfectly legal.
'Arresting the victim' was not common, but I recently learned is a growing trend among DAs. I just came back from a three day trauma conference so, yeah, I'm a bit testy. Idiot lawmakers, DAs and judges like the one in the Maine case cited infuriate me with their callous insensitivity and naive belief, especially when there are kids involved. They take a fragile family, tear it to shreds and then think somehow they did a good thing.
Sorry to hijack the thread like this. Giving it more thought, I completely agree with Maz, I think this approach is completely tasteless. The scene is illogical the way it's presented and how you suggest it will be used. Raping Sheila and then arresting her will only explode in your face in a very negative way. Rape/Arrest is an inappropriate and unnecessary plot device. Yeah, I'd urge boycotting a film that ineptly and glibly handled such a sensitive topic.
Frankly, Harmonica, this would require a deep understanding of human emotions and responses and advanced writing skills to carry off this scenario. In your shoes, I would seriously consider advice about replacing this concept completely. There are other ways to get to the ending you desire which are safer. You may need to adjust a few twists and turns but I think the payoff will be better.
If he gets pulled over by Tyler while Sheila is in the car with him, you visually introduce her. Henderson gets mouthy and Tyler steps over the line. Henderson, more than likely, could easily beat that for an improperly executed search by Tyler seeking drugs in Henderson's car. You could make her Henderson's girlfriend who witnesses a drug deal that later goes sour. She can still be called as a material witness to testify about a drug deal she witnessed and require protective custody. Keep it simple. It's a well trod path with plenty of film examples for you to borrow and adapt which don't require any detailed understanding of psychology or the law.
If Sheila is taking up half the script, then she's a lead protagonist like Tyler. That makes them a "couple". The dynamic has changed to one of "The Bodyguard" (lover/protector dynamic), a Bond girl (bad girl defects to the good side) or the Amidala/Anakin dynamic of Ep. 3 (good girl lost as the boy descends). You can mash those up.