I suppose I'm perplexed as to why Gabi simply didn't follow Kate and Sami's advice if it was the river incident Gabi was worried about.
By that point, all 3 had committed to it. Might as well let Kate and Sami protect you rather than taking matters into your own hands with a gun.
Or, alternatively, go to Rafe. I'm sure he would have understood why she agreed to dump the body since Nick had tried to rape her. And Rafe has a tendency to throw out his police badge when it comes to protecting people he likes.
Gabi had so many options. Geez, even EJ would have helped her. (Not that I think EJ cares about her that much, but he would have helped her out because of her association with Will, Sonny, Sami, and Ari.)