This has ben endemic for decades - hell centuries, if you count colonial times - in regards to medical charities operating in severely underserved regions. It's hard enough for medical professionals. Oftentimes you're forced to operate in a very limited fashion due to a lack of resources, knowing on the one hand that you can't provide care at a level you're used to, while on the other hand that you might be the only care the patient gets and that not providing any care at all can easily lead to certain death.
Those who are suited for that kind of work manage to balance improvisation with restraint and provide the highest quality care possible. Many others burn out from the pressure and return home. Some end up going through the looking glass and turn into cowboy physicians, reasoning that they can do just about whatever they want since it's all going to shit anyway. Suffice to say, the last category are dangerous.
I friend of mine went to Uganda as a medical student for her master's degree as part of a project studying pregnancies in rural teens. She worked at a medical station along with local nurses out in the bush. On day 1, she got asked by the nurses to do an emergency C-section. She didn't have a medical license. She'd never so much as observed a C-section since our OB/GYN course was the following semester. She wisely declined. The nurses did it themselves - as they usually did, having been trained in the procedure - but had asked my friend since they figured she was closer to being a doctor than they were.
My point with that anecdote is that some other medical student might actually have said yes in that scenario. Either out of arrogance, naivety or by feeling pressured. So it's no surprise whatsoever that completely untrained teens like the one in the OP can en up going through the looking glass even easier. It's good that she's facing legal consequences for this and I hope her story is spread as an object lesson. Volunteers need to understand that they're not heading out in the wild west and that they need to be able to set boundaries for what is ethical. Both for the sake of those they're helping and for their own sake.