Material rewards refers to being given things that are tangible , something that you can actually point at like physical support of her friends bringing their own trucks and physically helping her unpack.
Usually rewards are given to people because they also have been good like Tara has probably been a great friend to her friends and as a result they give her physcal material rewards in a form of physical assistance.
This quite hard. You probably get incarcerated anyways. But what I really think you should do is to hide the poison somewhere. Give the patient a proper medicine that will do no harm then when you leave the place, report it to the police or some law enforcers that the doctor tried to murder someone by presenting the poison.
