I know very little about the nursing profession, other than it undoubtedly is inherently very stressful, ER nursing likely having among the very highest stress levels. That being said, there are thousands of ER nurses who deal with the stress daily and for many years and don’t take their own lives.
My only comment is that some people have very personal demons that they quietly fight, sometimes until they feel they can fight no more.
Cricket, that about sums it up.