I'm like most of the hosts here, @Robert1917 , with my bedroom listing, in that I am sometimes called away when a guest is to be here in the house. I do write to the guest as soon as I know so that they know what's up and how to reach me. I don't have to let them know, but it's polite. I would want to know.
Were you staying in the sort of place that has lots of guests but no host around? There are quite a few of those (lots of them in Toronto), and it is not always clear in the listing that you are getting a sort of flophouse rather than a host's spare room. I fell into that trap earlier in the year when I needed a place with little time to find one. It turned out fine, but that was because nothing happened that required a host's intervention. It was off-season, so I had the whole echo-y place to myself, and everything was in good working order.
If something had happened, and if I had not been able to reach the host, I would have called Airbnb and asked them to try to reach the host. Airbnb often has a secondary contact number for hosts and guests. You don't have to stay when something uncomfortable or dangerous is happening. Are you okay?