Just because someone is an attending M.D. does not mean that she can "have you admitted" to the local hospital. She can "have you taken" for an evaluation. That's where her say-so ends. The emergency room doctor is under no obligation to admit you to the hospital no matter how eminently qualified a psychiatrist may have sent you there.
Here's a link. As it explains, what the attending pdoc can do is "initiate the process."
https://www.psychologytoday.com/blog...nst-their-will
Of course, E.R. doctors will take very seriously the
recommendation of a psychiatrist in the community who feels a patient is dangerously suicidal. But no doctor from a private office can dictate to any hospital that they must admit anyone.
"Initiating the process" of involuntarily forcing a patient to go to the hospital means that, first, the pdoc must convince police to compel the person to go. The police don't automatically take orders from anyone. The cops don't
have to take you to the hospital just because some doctor calls 911. Normally, however, they probably would trust the doctor's judgement. But they don't absolutely
have to. They would speak with both the patient and the doctor. They would look for evidence in the patient's speech and demeanor that indicates cause for concern. They might call paramedics. The paramedics might first consult by phone with the E.D. doc about what's going on. The E.D. doc might have the paramedics ask specific questions.
The mere fact that someone is a psychiatrist doesn't mean that person has the automatic authority to have anyone locked up. It might seem automatic because first responders would certainly take very seriously the recommendation of a psychiatrist reporting a patient as being in imminent danger of self-harm.
In the example above, the private attending pdoc didn't "defer to the ER doc for the final decision." The ER doc is the one has the right to make the final decision. The ER doc might chose to defer to the community psychiatrist, if the patient seems fine in the ER, but the ER doc feels the referring psychiatrist was seeing something worrisome that the patient may be covering up.