I can't stress this enough. Too often from the Sub-I/AI's I've worked with is that there's some level of performance anxiety in the weaker M4's. They have a fear of failing, so they go out of their way to avoid patients. I remember having it too, but I realized quickly that it was better to take a patient than to keep on avoiding it.
Case in point: At my program (Peds), the Sub-I/AI was on call overnight, and the two interns were not (its night float for interns). Two admissions overnight, done both by the Sub-I/AI and a transfer from CT surgery (a baby that was stable, but needed to complete a course of antibiotics, coordinate central line placement, and ultimately transfer to a rehab facility). One intern has two patients going home, so he picks up one of the admits. The second intern has 3 patients already, none going anywhere. The Sub-I/AI discharged all of her patients the previous day, so she takes one of the admits. So who should take the CT surgery transfer?
Intern A: 4 patients total, with one new admit
Intern B: 3 patients total
Sub-I/AI: One patient, new admit (who was admitted by the Sub-I/AI)
Let me sweeten the pot. The Sub-I/AI SAW and examined the CT transfer baby with an attending the previous evening, and got a complete sign-out on the patient from the attending (they went over everything). Who would it make sense to have round on the patient in the AM?
Guess what... the Sub-I/AI decides to ask intern A to take the patient (she knows that Intern B would point out the logical choice of who would take the patient). Seriously.
The best 4th year med students tend to take any opportunity to take the patient, especially in that situation with the patient load. Most residents will protect the Sub-I/AI anyways, if they have too many, the resident will step in and redistribute (or the interns will take any new admissions). If the M4 is wrong on rounds, so what, nobody is going to fail you on the spot (unless of course it really affected patient care). Its the effort in learning, its not about whether you are always right or you know how to handle every patient situation. Even showing the thought process to the residents and attendings goes a long way in showing one's clinical abilities.
That same Sub-I/AI in the above story? She also had a tendency to not complete all of the discharge work for the patient, didn't tell anyone, and the interns would get paged to finalize much of it. Learn from her mistakes, know your patients, do everything an intern would do. Ask for help, but try to do it on your own. Residents usually are your best friend, most will help with the difficult assessment and plans. Give it a shot, but don't be afraid to ask the residents first before you argue a big decision in front of the attending.