The first person Caster sees is either frigid-hoppy 'I'm not scared YOURE SCARED' Potato from the front, or a really odd lumpy shape (that'd be her tail) from behind.

Either way, the little homunculus sort of keeps vibrating for a second or so, before it registers what she just heard. Or rather, who she just heard. "Eh-"

IT'S....SAFETY!

"AAAAAH! CAAAAAAASTER!!!!"

Immediately, Potato launches over to try and latch onto the other's waist and/or leg. "CASTERIT'SALLFOGGYWEBROKETHEGRAILTOOMUCHTHISISTHEWORSTISEKAIENDING..!!"

That was probably (definitely) too fast to parse out, but at least she seems relieved to see the other? ...Or maybe not, that's tears. "Uhhuuuuu...it feels like we'll get spooky jump scares any minute..!!"

She's not really clued into the fact that none have happened just yet.