Director thought it would be cool I guess. The problem there is that it had little to do with the track of the plot. Unless you want to make the point that it showed how they saw her as a pawn or lesser minion since she was human. Kind of like how Stalin would shoot a general without thinking twice.

Yeah, the monster aliens were stupid. Even though she had control of them, they obviously were some type of cannibals and would eat anything even there master if push came to shove.
My job is to inform, not persuade- Dan Rather

Im confused about it too. But I am pretty sure it wasnt just because she was knocked into the mouth. I think it has something to do with her getting hit with pennies(copper) and then the other one pushes her in. As to the why maybe because she had a copper scent to her or she out lived her usefulness?

The big ones are stupid drones and she just got knocked into one's mouth and so it reflexively ate her.
"I mean, really, how many times will you look under Jabba's manboobs?"