It's not really hard to find the source of the noise; giant bugs tend to be very noticeable. In this case, a giant centipede.

Saya gasps when she sees it, and she would have replayed in her head all the information she had on these bugs, but she was a bit too busy to care; it was disgusting. And it was huge and set on attacking them, too. No time to be a scholar, right now.