Beleth probably would have been startled by River, even if she wasn't suffering from an exacerbation of jumpiness from the incident with Cade. However, she has indeed been a lot twitchier, jumping at even regular greetings. So when a girl appears to materialize in the rafters above Beleth, she does not react to it gracefully.

She lets out a strangled squawk of alarm, clutching her lute tightly as she jumps back--luckily, just to hit the stack of hay she'd been using as a backrest. Instead of toppling over, she just stirs dust and hay down onto her head as she plops back on her stack of hay she'd settled on. It takes a few seconds of looking from left to right, searching for the source of the voice, until she finally looks up.

Well. Now she feels silly. It's just a girl.

"I apologize--you're right, though. It's a bit like trying to dance, and I'm five steps ahead of my partner. Maybe if I play slower first...?"