I think that's an airsoft gun, the koyukkuri would had a broader hole, maybe even gotten tore appart, if those were real bullets, and the sound wouldn't be a "plick", unless they somehow hit you in the eye, there won't be any hazardous outcome from a accidental discharge. At least if she didn't just throw it up the air and caught it later as a "YAY!" exclamation.
All the people clenching their teeth, holding their breath and getting all excited crack me up every time, specially the post apocalyptic rider, but its an expected reaction coming from a yuka-chen performance