^ Don't worry, Matsuri is a bit eccentric but she is not irresponsible. Like in this video in which she talk about her realtion with Luna, Matsuri can be more calm than she is in stream most of the time. I think she love being all chaotic and flirty with the others girls.
A story with one of the Love Live girls losing her legs sounds like it has potential. Being spun around like this would make a lovely emotional climax.