Peridot goes with him, but only for part of the way. She can change her shape to try and look the part as much as she wants, but it doesn't change the fact that she's just not a skilled fighter. She'd been bracing herself to pull back on that tail, not hang on to it for dear life.

So. When Sans takes to the air, she gets flung halfway across the courtyard with an outraged squawk. That flash of green light makes it's third appearance tonight, as the engineer makes the switch back to bat mode in an attempt to better control her momentum. The net result of this is that it looks like someone has just punted a fuzzy soccer ball through the rain and over the Prince's finely manicured gardens; she squeaks as she hits the ground and bounces once, momentarily stunned.