Please don't hang up on emergency services. Even if it is an accidental call, they don't know that. All they know is that someone was breathing heavily on the phone, and not responding when they ask questions. Then, suddenly, you disconnected, and their mind goes to the worst possible scenario. Just say that it was an accident and don't freak them out.
I accidentally called 911 in class a few months ago. It was just a normal class, until I heard weird muffled sounds coming from my pocket. I checked, and lo and behold, it seems that I've triggered some emergency SOS system. In my panic, I hung up, and immediately realized that that was the worst thing I could have done at that moment. Luckily, the operator called back a few seconds later, and I explained that it was an accident and they said it was all good. That memory still haunts me to this day, and I wonder what terrifying thoughts the operator must have had when I ended that call abruptly.