It appears that Baby wasn't dead, and Zoë had to finish her off so she would start "singing."
Sadly, it looks like Flatbush the rabbit was in the wrong place at the wrong time. So much violence, I feel like I should blame it on the television. Zoë sits in front of CSI and Law and Order reruns all day long. It must feed her fantasies. But, alas, I must accept some measure of responsibility for this tragic turn of events.
It's frightening that someone who looks like this could have such a dark side.