The hopefully we'll be able to at least narrow down the list of suspects to the people who entered the bathroom around the time they the murder took place.

Surveillance often doesn't directly capture crime on camera, but is rather used to identify who traveled to and from the crime scene around the time of the incident

> What if lots of murders happened in bathrooms?

Then we would start putting cameras in bathrooms? Or start closing public bathrooms? Nobody wants to go into a bathroom and get murdered. We as a society are not going to just accept a high bathroom murder rate. Culture will adapt to reality, one way or another.

We create doors that physically limit access to one person at a time.