The need to see many many cases during your training so you can get lots of practice has been undermined in the last 10 years as efforts to limit "work hours" has scaled back the volume of patients interns and residents see. I think this has created a deficit, and I wager that graduates are leaving residencies less prepared (and more entitled) than in the past. If the problem was hours worked, it was not the volume of patients that was at its root, but rather the horse manure scut work that medical students and residents were expected to do as low wage and low status workers in the system. Scut work has no meaningful educational value. You should try to minimize scut work as much as possible, without drawing accusations that you're "not a team player" (a euphemism for "he fails to accept our prostitution of him") so that you can focus on meaningful learning. Sadly, scut work will always be a part of the culture of medicine, but make no mistake, it is the enemy of learning. Running a sample to the lab is hardly more educational than cleaning the men's room because the hospital won't hire enough janitors.
Fortunately, there are ways to get iterative practice, lots of it, without the distractions of scut work, if you can escape the wards when you're not doing meaningful patient care activities with associated learning opportunities. On my third year rotation, I used to sneak off to the medical library in the hospital and go through old issues of Chest, looking for the "Pearls" section in the back of each issue, and read the brief case summary and try to figure it out. The answer and a brief discussion were on the second page of the case. If "working up" a new admission takes 3 hours and you can read a Chest Pearl in 10 minutes, reading the Pearl is 20 times more efficient than working on the wards. Moreover, as a medical student, you are often told or you overhear the diagnosis before you even see a new patient, so it is NOT an unknown case, and it does NOT qualify for iterative practice of diagnosis. It has value to work up that patient from the perspective of eliciting the history and physical exam, organizing the narrative, and making the presentation to your superiors, but make no mistake, you are NOT practicing diagnosis when the diagnosis is known.
I soon learned that Sahn and Heffner, the editors of the Chest Pearls, began a book series called Pearls. I bought and devoured almost every one they published (except Sleep Pearls and TB Pearls - in keeping with what I said above, they were not unknowns and were thus not valuable to me - you knew every case was going to be Sleep Apnea or TB!). I also discovered these little picture books that the British put out, one after another called Diagnostic Picture Tests in Clinical Medicine, that have just an image of a rash, a deformity, a physical finding, an image, a slide, whatever, with the answer on the next page. They are awesome little books - I think I bought 30 or more of them (and they are going cheap on Amazon right now, so get on it!) By going through these Pearls and Picture Tests books during Med 3 and Med 4 (hint: Picture Tests fit in your coat pocket, so when you're "hurrying up to wait on the wards", you can study them), I "saw" literally thousands of unknown cases (with immediate, accurate feedback), literally the epitome of efficient, expert learning and iterative practice. Because of this, by the time I got to internship, many many things were simple, rapid pattern recognition for me. It was like I was years ahead of my training as a result of this kind of study. I have not recently looked, but I would bet that nowadays, the palette of such unknown case practice books has expanded significantly.
Besides asking to take on more patients during your rotations (at the risk of being labelled a "gunner" - which is utter complete hogwash, by the way - you are not gunning for anybody, you just want to be the best physician you can be. But you have been warned - being labelled a gunner can have impacts on your social reputation and thus your rotation evaluations, so conceal your "gunner" instincts if you can), there are other things you can do to enhance your learning opportunities. One is to not blow off 4th year. Fifteen years ago it was common to take easy "elective" rotations during the fourth year and travel and party a lot before the hard work of internship begins. Do NOT do this. I signed up for sub-internships, FOUR of them (maybe five, I don't remember). I did the usual Sub-I in cardiology, but also did two in Critical Care (one at my medical school, another at the Cleveland Clinic), and finally a Hepatology Sub-I. I recognized that there was a lot to learn in cardiology and in the ICU that I could not learn from my case books, and I wanted every opportunity to master those skills before internship, so I could, to my own satisfaction, take care of those patients as an intern. I changed an elective rotation to a Sub-I in hepatology when, after my MICU rotation, I realized that I was still "scared of" bleeding - that is, nothing I had ever read about in my books or seen up until then on my rotations had prepared me for what to do on a practical level when a patient is "bleeding out". (I learned on that hepatology rotation that it is actually quite simple, you get big IVs in place and order a lot of blood products.) Sub-Internships are far more efficient learning rotations than are the third year rotations because you know more and you're more effective, and as a result "they 'let you' do more." They were very very enriching experiences and they helped tremendously to prepare me for internship and residency. I suggest you fill your fourth year with as many "hard core" rotations (such as Sub-Internships) as you can to maximize your opportunities for dense, meaningful iterative practice. It pays off in spades during internship and residence, trust me.
Do it however you must, but "see" as many patients as you can, whether on the wards or in case or picture test books. But make sure the feedback you get on the accuracy of your predictions and diagnoses is both immediate and accurate - the subject of Part 3 of this series.