Vaccine Appointments?

So, today while working in the pharmacy, with about 15 mins til close I have a gentleman come in and inform my coworker, another DH that he had a vaccine appointment. I didn’t know those existed, and usually we only administer vaccines up to about 45-60 mins before closing so we can wrap things up efficiently. So, when we see people with appointments we honor them, but usually people come in earlier, not literally minutes before closing. So my coworker told him off, nicely of course, but he got heated and threw a hissy fit and stormed out. So now comes my question, how do these appointments work and why do they allow them to schedule so close to closing time? Doesn’t corporate know we’ve got things to do?