> How dumb would the officer look if he let a suspect destroy evidence, escape, or otherwise pull something on the claim that they have to pee?
There's a lot of ways in which the American system is deliberately set up to let some of the guilty go free and requires a certain degree of responsibility for those detained, charged, or imprisoned in order to preserve a set of rights that are important related to basic human dignity.
So yeah, particularly in situations like this, I'm comfortable saying sure, risk the possibility that (as yet established) evidence might be destroyed or that subjects of interest might escape detention. Strict detention practices should be sustained by meeting a high standard for suspicion.
But maybe better than that would be if we could have a system that included both reasonable pursuit of justice and a respect of basic rights. Seriously. Is it really impossible to give detainees and opportunity to urinate while protecting evidence? I doubt it. Search the damn bathroom, then search the detainee. Then, unless you've found anything that absolutely requires further undisturbed careful investigation and documentation, escort them to the bathroom for a reasonable amount of time. Part of the job. Particularly when you don't know that they're guilty of anything.