Hello, my friend.
Yep, it does, unfortunately, seem like you were the victim of yet another damn glitch, which I have no idea why it exists... You should need around 25 rounds to put her to sleep and trigger the ending, I have no idea why she didn't die, but thank you for bringing it up, I will see what I can do to fix that.
Every time I tested the game she died after 25 shots, in every build patch so far, so I don't know what went wrong on your end. Hopefully I can fix it. But you basically reached the ending almost haha.
Thank you so much for playing the game and I'm really sorry it bugged out. All these bugs are kinda depressing me to be honest, I really thought I worked out all the kinks..
God bless.