Hopeful but Helpless
Guy wasn't an expert in magic. His knowledge about the subject and everything it encompassed was severely limited and spanned only what the previous inhabitant of the body knew, as well as what he could gather through his own self-study. He wasn't "classically trained" in magic, not to a degree where he could boast about his expertise in the field, at least. Furthermore, the system-slash-golden-finger gifted to him by Mast did little to bolster his knowledge of magic. All in all, Guy was no better than your "Average Joe" except possibly with a far superior ability to recollect information. Sure Guy had his ingenuity and otherworldly thought processes, but how much did that really contribute towards his technical competency?
As he stood facing the convulsing body of his most peace-seeking student and the disease-riddled and near-death body of her attendant, Guy was faced with a troublesome predicament. What was he to do?