If carbon monoxide doesn't get you, you'll be fine.
But on a side note, we do it for hours in our i3. I go to my doctor appointments and the wife, who isn't allowed inside because of COVID rules, sits outside for however long on her tablet with the AC blasting. One of the primary reasons we bought an EV over an ICE vehicle. That and we get to charge it for free at our apartment complex. We're the only ones that own an EV, so the charger is always available, unless some jerk parks an ICE vehicle in the spot. But I complain and get their vehicle stickered for towing when they do.
In Nevada, with temps routinely hitting 115 (or worse) or so this summer, it does take quite a while to cool this car down. Sometimes 30-40 minutes into a trip. But once you do, you can cut back the AC quite a bit. Ours is black, but I would have preferred a white one. Very hard to find that color.