Lovely. Just lovely. Things were suddenly getting obscenely bad around here. Assuming that something terrible didn't just happen to everypony, they are at a loss for action. Time to rely on a cheap parlor trick, but hey, it's cutie-mark related for her.
Using the stone and echos and her already stated ability to throw and mask her voice, Staccata starts faking reinforcements.
"Just eight? Silly silly colt."
From another piece of cover: "Well they are mind-controlled so they aren't exactly big on the upswing."
Staccata is attempting to use the confusion to move into a more advantageous location, to either get a clear shot at the exit or go within striking distance of the big pony and his grenade launcher. If the latter is possible, he's hopefully not agile enough to stop her from lunge taking the thing.
"Maybe we should give you another chance to give up?