Hello, I first would like to mention that I am a 4th year med student undergoing clinical internships so I'd like to contribute a bit.
One key part of diagnosing diseases is physical examination and history taking. Some diseases have signs that give it away like McBurney's sign for acute appendicits. Maybe introduce some basic minigames to somewhat simulate the palpations and percussions we do irl? (Encountering enlarged organs, masses etc) I think it would also make the gameplay more varied too since I feel like the current gameplay gets a bit too repetitive after the first 3 patients.
Also I don't think we need to give everyone gowns. In my hospital's emergency we just treat people right away and don't give gowns at all.