I think your experience in the NURSING environment is just that, the nursing and CNA environment. As a MA in a primary care office, yes I have an environment that is more 'feminine' and chatty, but then that is ONLY within the MA pool. That being said, everyone is a work-family in our current group and it actually fosters an environment where the patient care is paramount while joking around to deal with the fact that we are taking care of grumpy patients, foul urine, wild looking wounds, cancer patients that are actively dying, etc .
The PAs themselves are less gossipy, more focused on their work, same with the Doctors I work for. I think you need to just be aware of the culture of the group that you are with and within certain specialties you are going to have more of that levity than others.
I think Going the ER route is great but just know that you are going to have to get comfortable with the office/floor politics and gossip wherever you go.