She may not have felt well enough to do that, in which case she should have told the receptionist that, and told them to break the door down or told them where a spare key was if they had one close by. I once had to call emergency services because I had been passing out and there was no way I could have made it to the door. I told them where the key was hidden and they made it to me in time. In cases of heart attack etc, any extra movement could mean the difference between life and death. Goodness knows why she attempted to go to the door once they got there. When you are really sick, you don't think clearly.

Alright, it is still the 911 person's fault then. There is usually a good 5-10 minutes between when you make the call and when they get there. You can't tell me that the concept of entry didn't occur to the receptionist.

I am sure that the receptionist told her about it and she did try to make it to the door, but there is the possibility that the lady was so out of it that she forgot about it, or was just making it to the door when it was knocked down. Nobody, neither the OP, is at fault.