This is not all that uncommon. Holding cells are not always next to/near places where people tend to be. Many of them are closets that were intended to hold someone for a very short period of time and thus not even equipped with a commode and sink. My recollection is that a person is more likely to be "abandoned" in courthouse holding cells than in ones in jails or police stations - if only because there are people moving about near the holding cells in jails/police stations, while courthouses get shut up at night and over weekends.
Only very recently has the War on Some Things progressed to the point where detainees are taken to a Task Force administrative area for processing instead of to a jail. This seems to have come about because of turf guarding by both sides - the jails do not want their limited resource of holding cells taken up by someone who administratively "belongs" to some other agency, and Task Forces seem to want to exercise total control over the people they detain in order to leverage the process in favor of the goals of the War on whatever they were formed to combat. (Put a detainee in a jail holding cell and you lose much of the ability to ignore or trample on civil/constitutional rights.)
The problem is that these Task Force administrative areas are not always staffed 24/7, and there are no staff designated to regularly and periodically check on the physical status of detainees. To be quite blunt, it often is known only to the person putting someone in one of these holding cells that the person is there. While they will never admit it, I've go a fiver that says that was what happened.
The DEA introduced national detention standards as a result of the ordeal involving Daniel Chong, including daily inspections and a requirement for cameras in cells
In other words, the bare minimum standards for police stations, jails, and prisons.
I'm not sure I would have agreed to settle the suit, both because I am pretty sure a jury would be quite outraged and because not a single head seems to have rolled. Yeah, new "standards" were put in place - that should have been there all along. Can you say "gross negligence"? I knew you could, and I'm pretty sure a jury would have been able to as well.
stay safe.