Earlier quoted context omitted.
You need to reiterate it until you elicit an answer
Are they legally required to give you an answer? If not, this could go on for hours, and if their intention was to restrict your movement then they've already succeeded.
For that matter, I suspect most will realize that they aren't going to get anywhere with someone who's knowledgeable and disciplined enough to only say "Am I free to leave?", and will move on for easier prey. Spending "hours" in such a game isn't going to generate the arrest statistics they need, they'd only make that sort of investment if it was a really serious felony. (Unless of course their reward was an internal one of successful harassment ... and this sounds very tedious.)