1) the ai stuff is an ok place to start
2) f*** them
3) if hr isn't completely on your side, saying that that guy was in the wrong, they can go f*** themselves.
4) when you meet with them, go over the exact policy for taking a break, like when they can happen, where you are permitted to be, and what you have to be doing. Because if you weren't doing anything that wasn't prohibited in the policy why they f*** are they bothering you on your break? How are they going to make up for it? If it was an unpaid, you damn well better be getting paid for it or else it's going to department of labor for wage theft.
5) they're the ones asking workers to work 16 fucking hours. If it's so shitty that they can't find enough bodies to fill eight or 10 hour shifts, they need to be taking care of y'all, not trying to f*** you over. The only reason that guy should have been going into the break room is to bring you chips and an energy drink. And make sure hr knows that asshole is the reason you're forever declining any extra hours.
6) f*** being in the workforce, too. They're paying you less than the profits your labor creates (otherwise they would have had you working zero hours that day instead of 16); they're getting money because of what you do and they're actively trying to make the conditions you work in worse instead of better.
7) f*** them.