Walk any hospital at 10 a.m. and you can feel it: the building either moves or it doesn't. Leaders talk about gridlock the way they talk about weather: unpredictable, unfair, arriving from nowhere. But it doesn't arrive from nowhere. Gridlock follows rules.
A discharge that slips an hour doesn't cost an hour; it cascades. The bed stays full, so the ED boards, so the ambulance offload delays, so tonight's admissions stack into tomorrow's morning. Queues compound. Bottlenecks migrate. The system behaves like a system, which is the good news, because systems can be engineered.
I call this Flow Physics: the discipline of treating a hospital's movement problems as findable, nameable, fixable causes rather than fate. The single highest-leverage place to apply it is the layer nobody watches: transport and support services, the circulatory system that every clinical plan silently depends on.
Once you can see the rules, you stop blaming the weather. That shift, from weather to physics, is where every flow transformation I've ever seen begins.