How should this delicate situation be handled?

Marcie is a new client and a 22-year-old female who works as a receptionist in a doctor’s office. She has just revealed to you during the intake session that she has recently lost interest in most activities, has been sleeping a great deal yet feels tired all the time, and sometimes wishes she could cease to exist. She mentioned feeling as though she has been “on an emotional roller coaster” during the past year, throughout her on-again/off-again relationship with a 35-year-old married man. The last breakup with him seemed final, and Marcie has felt herself sinking deeper and deeper into depression ever since. When probed further about suicidal ideations, Marcie admitted that she has considered killing herself, although she is uncertain whether or not she would actually do it. She said that she is currently in possession of a gun that her friend allowed her to keep in her home following a rash of burglaries in the neighborhood, but she does not know whether she would actually use it.

You have consulted with your supervisor, who has agreed that Marcie should be referred immediately for a psychiatric evaluation and has instructed you to arrange for Marcie to go directly from your office to a nearby hospital. Marcie told you that her mother accompanied her and is in the waiting room, but she has emphatically stated that she does not want her mother to know what is going on with her. How should this delicate situation be handled? Why? What are three ethical and/or legal concerns about this case?