I can't speak on the behalf of what other people comprehend, I can only speak for myself.
The fact that the ER gave her one covid test, which came out negative should been enough, especially with the background info which we provided.
We went to the ER because my daughter blacked out in my wife's arms right after telling her that she couldn't feel her heart, and then vomited on the floor. After the fire department arrived from the 911 call, and did the initial check, they suggested that we drive her to the ER instead of having an ambulance (which hadn't arrived yet) do it, as the ER is only 5-minutes from our house. We didn't think that the ER doctor would dismiss what our other doctor's diagnosis had been, but she did. In retrospect we should have gone to urgent care at a different facility which was in the same network as her PCP, but that would have been an additional 15-minute drive.