This is exactly where my mind went. I can't imagine she was just leaving school and decided becoming a nurse would be the best route to killing babies. Or maybe I just don't want to.
A common thing with killers is that they enjoy the rush, I wonder if that's something that developed while she was working, as in she felt that during her legitimate duties and had to push it further and on her timetable.
A monster, regardless.
If you had them make this drink without the coffee, it wouldn't taste the same... That's like saying people drink old fashioneds because they don't like the taste of whisky. It's an ingredient.