Two sentences showing precisely why no one can trust the police. Not only are they completely unaccountable, but they will trample your first amendment rights and do so with smug amusement in full public view. These are the kinds of people we're supposed to be happy to give massive surveillance power to?
"I will take as long as I need, to get you to comply. Your resistance doesn't make this go away, it just prolongs the inevitable."
Someone can have more than enough time and energy for a task, but prefer to do other tasks as well.
He would probably prefer to spend a shift sitting around drinking coffee than hauling people out of a meeting. Unless he's gung-ho or a bit of a sadist, as people elsewhere on the thread have implied. Just for giggles I'll make the "energy" argument too: How long can he maintain a vigorous struggle against a truly resistive subject, or a whole room full of them? How long can he keep up with someone who is in athletic running shape? Not "all night" surely. He will try to avoid having it come to that, by controlling the situation early, calling for backup, and/or relying on various technologies.