Thank you for the thoughtful response. Switching to medicine is something I've been contemplating for a couple of months and though about all pros & cons, best-, worst-, average-, expected outcomes extensively, yet I still feel at a lock. To put it shortly, my best case is better staying at my current program and my worst case is worse. The average case is too difficult to determine as the probabilities I assign to each case are speculative.

As for a PhD in medicine being easier, I don't mean that doing the actual PhD is easier but rather the entrance requirements are. The medical school in my country is good so I can just do my PhD there which would be quite easy. On the other hand, the technical school I'm in doesn't have that much research in machine learning so I'd have to apply abroad which would make things much harder. Not to mention that machine learning is a hot area and perhaps the most competitive of all PhD-subjects.