All these buses analogy isn't exactly the same because they still have the option to stop somewhere, which give the passengers the assurance that if they can't hold it's not the end of the world. Taking that into consideration, I think it could solve most people's bathroom concern by adding bathroom stops to the loop, in the case of semi-emergency, ideally a pod should be able to make a stop upon request within 5-10 minutes without disrupting other pods. Some financial incentive might be needed for encouraging people to hold longer but I do see legal risks in that approach.