Hello and welcome!!! My opinion is that you shouldn't second guess yourself. If this is the topic you have in mind for argumentative purposes, then clearly you know you can support the "theories" at hand. You might not want to say definitively "...ARE more driven by salary..." rather, "some staff members MAY be more inclined to keep their livelihood secure rather than cause a controversy surrounding the death or injury of a stranger.." or something like that. You might also want to mention, just for argumentative purposes, that a lot of decisions and policies among hospital personnel are driven by the need for protection from medical malpractice lawsuits, etc.
Something like that :). When you have finished with your essay I'd be glad to review it and other that that, just begin with a strong opening statement and follow it by fact and clarity in what you are defending. List what we have talked about and anything else you'd like to say in a clear and organized way and finish with a nice summary.
I hope this has been helpful. Good luck :)