"You seem to replace your brain with your heart,
You take things so hard, and then you fall apart,
You try to explain, but before you can start,
Those cry baby tears come out of the dark,
(Someone’s turning the handle to the faucet in your eyes,
You pour it out where everyone can see,
Your heart’s too big for your body, it’s why it won’t fit inside,
You pour it out where everyone can see)
They call you cry baby, cry baby,
But you don’t fucking care,
Cry baby, cry baby,
So you laugh through your tears,
Cry baby, cry baby,
Cause you don’t fucking care,
Tears fall to the ground, we’ll just let them drown,”
https://www.youtube.com/watch?v=YGpydKymkIo

Someone's really upset and is gonna go do a murder to just get out
Kiyotaka is dead and Kitty is broken, they do not care anymore, they want to die, and they have noticed Byakuya's staying up late doing research, and they just do not like him, they think he's dangerous and likely to get everyone else killed just from being stubborn and feeding his own ego, so they figure kill two birds with one stone, nearly literally, kill him and by admitting to it get themselves killed, they just want Kiyotaka, nothing is worth it to them anymore, so may as well try to help their friends out, remove someone they view as bad and dangerous, while also removing themselves from this hell they're suffering through, they, of course, don't actually get to do this, but if given the chance it's what they'd go for, baseball bat to the back of the head to a distracted Byakuya

"Cry Baby"-Melanie Martinez
Kitty-Me