I have had people call 911 from the waiting room on many occasions, usually by disgruntled individuals with relatively non-urgent complaints who felt that their problem deserved attention ahead of minor complaints such as chest pain. Mostly by people who were not as sick as they thought they were. Some who thought, erroneously, that they would be magically whisked into the back door and immediately ensconsed in a comfy bed, or taken to another hospital. Never, ever have I had an 11 year old female do it for attention.
(Heard on police scanner): "Got a 911 hang up from XXX st., the ER. Came from a phone in the waiting room".