You could always go the nurse practitioner route, instead of PA, since you're planning on becoming a nurse anyway.
In my state, NP's have a lot more autonomy than PA's.
If you want ER, I think being an EMT will help you more, as opposed to CNA.
You can most likely get a job in an ER as just a tech, before doing CNA or EMT etc, to see if you like it first.
I know a lot of guys who are nurses...especially in areas like ER, ICU, and cath lab.
Good luck with whatever you do!