This is a good question. What would the boy want her to do...

"If you're not a real witch, then you won't melt if we splash you with water!"

...Uh oh, that's getting kind of dangerous. Some water splashing probably won't do much, but if that boy gets overzealous... Rokurou tries to hurry along. He's just two more "stops" away from the pearl, but this also means he's a lot closer to them and at a greater risk of being seen. The moment he tries to check if he's clear, he sees that dog staring right in his direction. He manages to hide, but the dog is now growling.