I think the ending is wrong as it is. With her just killing her husband like that in cold blood. One could argue self defense but she had the gun and the advantage. And there really isn't much or any evidence to back her up. She will end up going to prison and doing time.
Anyway, I think a better ending would have her just simply getting away with it and living her life free from her abusive husband. I dunno. I'm just so sick and tired of the bad guy ALWAYS getting killed at the end of movies. Why not just have them getting caught and going to jail instead?
I suspect you're not being serious, but if you are:
Ben will vouch for her, for one thing. Martin viciously assaulted him. That will help the credibility of the situation a LOT. And Ben (who knows the background anyway) saw Martin break into Laura's house & threaten her.
Martin's been keeping Laura a virtual prisoner for their whole marriage. He is an abusive brute, and Laura never felt she could stand up to him till the end. Even then, she never wanted to kill him. But once the shmuck Martin tells her that if she refuses to return with him, she's dead....she finds the courage to stand up to him at last.
Lastly, the ending as we see it is more cinematically thrilling than Martin just going to prison.
I'd say this cloud is Cumulo Nimbus. Didn't he discover America? Penfold, shush.
She shot and killed a defenseless man in cold blood. He didn't have a weapon. It's Ben's word against physical evidence and I don't think that will hold up.